But why though? All of these male tickling scenes are for humour or for the story they're not there to appeal to people who get off on seeing men being tickle tortured. Why should any show be incentivized to include more women in the same situations unless the real reason was for people like us? And actually, thinking about it for a few days more, I'm not convinced /m tickle torture scenes are that much more common.
Up above, someone listed several /f scenes in cartoons like this Batman one and even left out a couple. It's not like they never happen, and it's also not like /m scenes are happening all the time. I can't think of that many. I would the split is probably not far off being even. But I don't know, maybe I'm aware of way less /m scenes than I realize.