The if you don't like something don't read it argument is annoying, how can you know if you haven't read it
I think it’s sometimes justified, when someone weighs in with criticism of an OP because the subject of the thread annoys them for some reason, but they haven’t bothered to really read what the thread is about.
For example, recently someone started a thread about cycling, intended to support & exchange ideas for those thinking of taking up cycling or getting back into it, advice about clothing, types of bikes etc.
But someone just had to stick their oar in, complaining about cyclists on the roads & what a nuisance they were, spoiling what had until then been a friendly supportive thread.
It was politely suggested that the didn’t have to read a positive thread about cycling, and they were free to start their own moaning one if they wanted to.