Personally, meaningless animations and memes cause me a great deal of distress. It's enough to drive me away from participating in Slack at work because I find it exponentially hard to scan the channel for important things if the channel is full of pointless motion and distraction.

If I still was working somewhere it was a problem I'd be inclined to get a note from a doctor and go through the process to formally get accommodation for a disability.

HN does the right thing in blocking Emoji in comments because all you get for Emoji is a defining down of people's ability to communicate and lawsuits because some rando sent somebody else an eggplant emoji.

I've personally never had a good experience with teams, which is sad. If you don't like gifs then don't allow them in channels where you don't want them (possible on other platforms)