I'm very sorry Stew. None of us intended that.
Should we maybe coordinate to use a special font color, or sig or something?
I hate the idea of causing distress.
I think it's good to keep in mind jokes are there to make others laugh. If it makes someone cry, there's no harm in telling them you didn't intend to hurt them (I'd hope you didn't intend to, or it wasn't really a joke).
There is harm in trying to bully them into laughing or telling them off for not finding it funny. Which is what happened last year (e.g., lighten up, get a sense of humour, there's something wrong with you if you didn't find that funny). That was far more unpleasant than the jokes themselves.
It was only a few people doing that, but it only takes a few. If you cuffed them round the ear in the days after April Fools, that'd make it far nicer. An unfunny joke is easy to forget. Someone attacking you for not finding is funny is much harder.