I wrote a mean response, but let me just say you are being overwhelmingly condescending starting with your initial response. I will give you the benefit of the doubt and assume you don't know you are talking down to people, but you opened the door when you claim you did not talk down to them despite that being your primary interaction style. I encourage you to use AI to help edit your responses in the future if you are actually not aware of this.

I pasted it into chatgpt with the prompt "analyze the tone of the-grump and check for condescending language and tone. give examples if any." and here is what it says:

Yes, several of the-grump's comments read as condescending. Defending the author from harsh criticism is reasonable, but some of the language used in that defense also talks down to others.

  Were you not also taught to "say something nice or nothing at all?"

This is the clearest example. Invoking a childhood manners lesson positions the other person as someone who needs basic correction.

  You don't see how it's nasty, and then you pile your own nastiness on top.

This is scolding. It treats disagreement as a failure to recognize something obvious, rather than explaining which wording crossed a line.

  Get a life ... instead of spilling your bile on somebody sharing their work.

This is primarily insulting and contemptuous. Hostility is clearer here than condescension specifically.

  And who has an interest in your opinion, pray tell.

This is sarcastic and dismissive. "Pray tell" adds a mocking, superior tone, although the remark also echoes the preceding commenter's dismissal of the-grump's opinion.

  That's what some here don't seem to understand, that there's a way to put things gently...

This presents others as lacking basic interpersonal understanding while placing the speaker in the role of teaching it.