There’s a meme on Twitter among what I think of as the Woke Left : a group that’s hard to define, but one you might associate with some or all of the following concepts: open borders, tone policing, privilege, “sex work is work”, no platforming, Corbynism.

The meme is this. You put heavy quote marks around the phrase “legitimate concerns” – maybe make it “““legitimate concerns””” if you really want to have them rolling in the aisles – particularly when it comes to discussions of immigration. The implication is that there are no such things as legitimate concerns . Those who claim to have them are probably, underneath it all, just racists, albeit with a more sophisticated vocabulary than your average EDL thug.

Really, though, this a dismissive rhetorical trick to avoid engaging with the whole subject. (And a dangerous one if you don’t want to look silly: Jeremy Corbyn himself stood up in Scotland last week and promised that Brexit would bring an end to immigrants undercutting the wages of British workers. Turns out even he has legitimate concerns, or perhaps these are also just “legitimate concerns”?)

The “legitimate concerns” meme is very Twitter: snarky, a bit dickish, superior. I understand the impulse: sometimes the temptation to rebut an opponent’s point by turning it up to 11 is irresistible. The trouble is that it absolves you of the hard work of argument. If you truly believe that immigration doesn’t drive down wages, there is academic evidence available to back up that thesis. But you also have to engage with the fact that, as one political adviser once put it, “voters don’t live their lives in the macro”.

Even if immigration is good for the health of the economy overall (and it has been, in the case of Britain), it might not feel that way to you, as an agency brings over dozens of eastern Europeans to work in the nearby warehouse. A left-wing case for immigration must include sharing its benefits more fairly: allocating money to help schoolchildren whose first language is not English, for example. Otherwise it feels to some voters as though their communities are changing rapidly, with no upside for them.

All those are arguments that a party such as Labour could, and should, make. There has been no robust defence of immigration in mainstream politics for many years. Instead, the default setting on the left has been to dodge the question, and try to suggest that it’s vaguely illegitimate. The trouble is that silence does not mean agreement.

Worse, the field is abandoned to the hard right, who are comfortable not only with the idea that some concerns are legitimate, but that all of them are, no matter how little basis they have in fact. The entire debate is poisoned and increasingly polarised. Now it feels like a betrayal of your “side” even to contemplate a dialogue. Sticking to the platitudes is the safest and easiest course.

The same dynamic is now apparent with transgender issues. A big debate has opened up about the relationship between biological sex and cultural gender, and how that should be inscribed in law. The left, by and large, is ducking it – using the same put-downs as it did with immigration.

Want to talk about how letting people self-define their gender might affect female-only spaces such as prisons and changing rooms? Then you’re a bigot, cloaking your bigotry in the language of “legitimate concerns”. Want to discuss whether we are rushing to medicalise gender non-conforming children because they and their desperate parents have been sold the idea there is a universal “fix” for their profound, genuine unhappiness? These are yet more “legitimate concerns” that can be dismissed, even as medical professionals warn that not every gender non-conforming child will benefit from puberty blockers and (later) medical transition.

Even worse, the shoutiest commentators refuse to engage with detail and complexity. They try to reduce these sensitive questions down to a simple test: are you in favour of “trans rights” or not? This is, of course, a trap. It’s designed to end the conversation: a thought-stopping cliché.

We should all be in favour of the right of transgender people to live their lives free of discrimination, harassment and abuse. When I see self-described radical feminists tweeting at trans women that they are delusional, perverted men, I recoil. But the right of someone who has been through male puberty, with the consequences for skeleton and muscle development that brings, to compete in women’s sports that depend on raw strength? That’s more difficult. There is no human right to compete in the Olympics. RuPaul’s Drag Race – a reality television contest for gay men – can exclude non-trans women, but is attacked for excluding trans women? You’ve lost me.

Our ideas about gender are undergoing a profound shift. I hope that they will end up in a place where a boy can wear a princess dress without people assuming he is “really” a girl. I hope that they will end up in a place where a trans man can get the medical treatment he needs to live his life to the fullest without people wondering if he is “really” a woman. I hope that we can recognise that women’s concerns about female-only spaces are not hysteria, and that even if you think they are overblown, they merit engagement rather than outright dismissal.

The left’s blithe rejection of “legitimate concerns” about immigration led us to Brexit. So please, if you think that concerns about gender ID reforms are wrong, explain why. Don’t offer wafty bromides about “trans rights” without explaining what you’re talking about. Don’t excuse yourself from the hard work of politics with a wave of the hand. If those concerns aren’t legitimate, your explanation might make a difference. Whereas snarky, superior air quotes will only make you feel virtuous.