I don't believe you.
Making App integrations for Slack to basically anything is pretty close to a joyful experience, the rest of it is comparable to other chat systems perhaps, but are you really telling me with a straight face that developing applications atop Teams (that do more than just plug other Microsoft things together) is actually a superior experience?
I get that opinions are subjective and all that, but so you understand: I'm having the same reaction as if someone said to you that contracting gangrene is preferable to a walk in the park.
As for your reaction: if your experience is so different, a useful attitude might be to ask why you have such an absurdly negative viewpoint.
To tell you the truth I always assumed it was because Microsoft didn’t really care about chatops or any integration that was not within their ecosystem (or a website). The experience is consistent with that viewpoint.