Microsoft first revealed it would allow Xbox gamers to play against PS4 and PC players at E3 last year, and Sony’s initial reaction seemed like it would be open to the idea. "We would be happy to have the conversation with any publishers or developers who are interested in cross platform play,” said a Sony spokesperson at the time. This week at E3, both Rocket League and Minecraft are going cross-platform play, allowing players on Nintendo’s Switch, a Windows PC, Mac, or Xbox One to play against each other. The big missing part is Sony’s PlayStation 4.

In an interview with Eurogamer, Jim Ryan, head of global sales and marketing for PlayStation, attempted to defend Sony’s block of cross-platform play. “We have a contract with the people who go online with us, that we look after them and they are within the PlayStation curated universe,” says Ryan. “Exposing what in many cases are children to external influences we have no ability to manage or look after, it’s something we have to think about very carefully.”

Nintendo is supporting cross-platform play

Sony’s excuse might seem feasible if it weren’t for Nintendo, a family-oriented company, enabling the cross-platform play on its Switch console for both Rocket League and Minecraft. Instead, Sony’s excuse just looks user-hostile given all of its main rivals have enabled this functionality. Xbox chief Phil Spencer isn’t happy with the response, either. Polygon reports that Spencer seemed offended by Sony’s excuse in an interview with Giant Bomb. “The fact that somebody would kind of make an assertion that somehow we’re not keeping Minecraft players safe, I found — not only from a Microsoft perspective, but from a game industry perspective — like, I don’t know why that has to become the dialogue. That doesn’t seem healthy for anyone,” says Spencer.

Microsoft has repeatedly reached out to Sony to try and enable this cross-platform play. “We would love to work with Sony to bring players on PlayStation 4 into our united ecosystem as well,” says a Microsoft spokesperson in a statement to Polygon. Even Spencer says “the door is open,” encouraging Sony to change its stance. Psyonix even told Polygon that cross-network play in Rocket League “would be up and running in less than an hour all over the world” if Sony removed its blocks.

Sony is blocking because its PS4 sales are strong

It’s unlikely that Microsoft would be encouraging this type of cross-network play if it was still in a position of power and selling the most consoles in the US each month. Now that Microsoft is struggling to compete with Sony’s impressive PlayStation 4 sales, it needs to encourage things like cross-network play. Sony is in a much stronger position, and blocking cross-platform play simply encourages gamers to buy a PS4 if they want to play with their friends. If you’re the only one in your group of friends with an Xbox One then you’re probably going to be waiting until Sony’s PlayStation sales slip for any type of cross-platform play.

This isn’t the first time the two companies have been at odds over gaming features that have been blocked. Microsoft has blocked mods in the past in games like Unreal Tournament 3, and it has refused to enable keyboard and mouse support on its Xbox 360 and Xbox One consoles. Sony enabled mods and keyboard / mouse support on its PlayStation 3 and PlayStation 4 consoles.

Update, 7AM ET: article updated to remove mention of Fallout 4 mods.