Discord doesn't do anything with the number, it's just to combat bots and trolls.
Moderators also need to have 2FA enabled when a Discord server is set to "Community". This is purely for security.
Provided the community has clear rules on where to post gifs/memes redirecting the user is fine. Of course it should be a gentle reminder and not feel as if the user is getting berated.
If they still get pissy after that, it's more on the user. A reminder to follow the rules is not a personal attack.
So just scroll up? It's not like when a message is off the screen, it's gone forever. Or do you never catch up on messages that you missed while offline and just go in from there?
The good thing is that you can choose to ignore the meme, reply to the interesting thought and continue the conversation. Then if you keep the conversation going, it could be made a thread if people are interested in it.
Also a honeypot for memes is helpful so people are less inclined to drop them in general channels
I tried to look you up but I'll do it tomorrow