> More likely they're just a bit too earnest and as a result try to correct others and overcompensate.
You are assuming way too much good faith. For every one that does it in earnest there's probably 10 grifters just taking advantage of the situation for their own personal benefit:
The real reason seems to me like virtue-signalling. They don't care whether they're personally offended, as that would require burning social "points" by rocking the boat but potentially getting no outcome out of it (nobody else might agree). It's "safer" to just suck it up than sacrifice social points especially when you're on the lowest ranks.
They also don't know nor care whether the protected class they are worried about is actually going to be offended. Again, rocking the boat and burning social capital for little personal benefit.
This leaves the argument of earning social capital by virtue signaling among like-minded peers. Pick a common issue you already know is popular within your target "market" (racism, sexism, "diversity & inclusion", etc) and raise the problem. This doesn't risk any social capital, after all, people like you won't disagree (for the same reasons) and people that might be on the fence or would like to add nuance wouldn't want to risk their social capital in fear of being labelled a racist/etc. It also transcends the ranks - if anything, a higher-ranking person in the company would risk much more by speaking out than someone on your rank or lower.
This eventually results in a positive feedback loop where everything will become offensive given enough time and those who disagree either comply or get pushed out. That's how you get bullshit like GitHub's "main" branch which helps nobody while continuing to sell services to ICE which you could argue actually hurts minorities.