For others who've internalized this sort of message in the past, either about themselves or about others:

I internalized the "just make it yourself if you don't like it!!" message for a long time, and I don't think the degree to which I did is helpful. I began feeling like I needed to take responsibility for every and all content and community that I wanted to see, and that's simply not possible for one person to do.

There's nothing wrong with giving negative feedback, and imho, responses like this are usually not helpful. People who mean to give an encouraging, supportive, welcoming message inviting me to contribute what I have to contribute usually don't take this kind of tone. I don't think it's a cultural difference. I think it's just an off-topic ad-hom in response to a normal, appropriate, and expected post in an appropriate sub by a known demographic that's seeking an environment to speak without censorship.

Do I think this person deserves my response? No. Do I think the people who, like me, internalized this kind of message and attitude towards themselves, and tried to take too much on, and expected too little from others who claimed to be offering them something, deserve a response? Yes.