YouTube just censored another one of Prager University’s educational videos, and this time YouTube went after one criticizing censorship.

Prager University also goes by Prager U. The video in question features Wall Street Journal columnist Kimberly Strassel, who explains common tactics leftists use to shut down free speech from conservatives, including intimidation, harassment, and blackmail.

Beginning in 2010, the IRS intentionally targeted conservative nonprofit groups and delayed approving their tax-exempt non-profit status an attempt to render them politically impotent during the 2012 election, Strassel explains.

In Wisconsin, a Democratic prosecutor went after conservatives in a shadow campaign finance investigation. The real reason for the pre-dawn raids on conservative activists’ homes and the subsequent gag orders legally compelling them to stay quiet about it all were to enact revenge for their support of Republican Gov. Scott Walker, she says.

These are two of several examples she highlights in this five-minute-long video decrying censorship of one’s political opponents, which YouTube decided to censor by placing it on “restricted mode.”It’s common for schools and parents to place their YouTube account on restricted mode to keep obscene or graphic content away from children. But PragerU’s videos, including the aforementioned one about censorship, are G-rated, so it’s unclear why the video platform is placing these videos on the naughty list.

Get this: I do a Prager U video on the left shutting down the right, and Youtube censors it. #CENSORED. https://t.co/1fXrZqaRuZ — Kimberley Strassel (@KimStrassel) October 27, 2016

This isn’t the first time YouTube has censored one of PragerU’s videos. At least 21 others produced by the conservative, nonprofit educational organization have been placed on “restricted mode.”

PragerU is circulating a petition to stop the censorship. At the time of publication, it has more than 76,000 signatures.