I am guilty of retaliating with slow play, time wasting and watching replays when my opponent watches a replay or long celebration.
I've decided that the only way to try and encourage people to skip replays is to be the better person and just continue to play normally and skip everything as normal.
Then send a simple message at the end saying "to skip straight to kick off lb+RB. gg"
Only we can make the community less toxic through leading by example.