For instance in schools you are not allowed to talk about gender identity in some states.
Often you are not allowed to teach about slavery either.
You are also often not allowed as a teacher or just working at the school to say if you anything other than straight.
That would actually be illegal to enforce in countries with better protected freedom of speech.
One school banned a graphic novel Maus about holocaust despite it has won a Pulitzer.
Aaron Swartz was persecuted by authorities to the point of suicide for legally copying and trying to make information available to the public, that should by definition of the terms they were kept, be available to the public, but were not.
In the military you are not allowed to say you are gay.

The terrorist acts has secret courts giving secret organisations power to silence companies on for instance when information is demanded on users from companies like Google, Facebook, Microsoft Apple, also when the demands are illegal by normal law, generally because they are too wide. Other often targeted companies are also mail services with increased security. This is monitored by a secret club in congress. This is part of what Obama called a "balanced" approach.
Failure to respect these secret courts, will result in you being judged by same secret courts!!!
You are not even allowed to seek outside council or mention it to anybody for help on what to do.

In much the same way there are restriction on the "free" press, which make it impossible for the press to air concerns. This is probably why you have a multitude of stories like this:
https://www.pewresearch.org/short-reads/2023/05/02/most-u-s-journalists-are-concerned-about-press-freedoms/

What's notable is that the more experience a journalist has, the more likely he is aware there's a problem. But there are no specifics on exactly what the problems are.

On public TV you cannot air profanity:

https://www.tvguide.com/news/features/tv-censorship-nudity-profanity/

outlined the swear words that are still taboo on broadcast TV to this day -- ended up causing the highest court to rule that the Federal Communications Commission had the authority to regulate what viewers see on broadcast media.

Beep beep beep, it's so incredibly stupid!!!!

So maybe the meme was self censored, but it was out of a habit of doing so because in some situations you MUST, meaning your freedom of speech is restricted. By doing so on the meme, it parrots more official channels.

USA is probably the most censored country of the free world they claim to protect, and you don't even know it!?!?!