I'm a professional developer and have been working with database-driven web applications since 1997, so I think I know what I'm talking about. I am completely capable of stripping out these paragraph tags on the server, but that's not the point for me posting here.
I don't get the animosity. I know (KNOW - because I've written HTML editors from scratch - not to the extreme level of detail that this editor is written in, but detailed enough to have served as the front end for a from-scratch CMS I built in 2002), and I know that somewhere in this code is a line that takes my content variable (say that it looks like "var s='<div>hello world</div><div>some other stuff</div>'"), and does this to it: "var tinymceoutput="<p>" + s + "</p>".
If you are weary of explaining why you do this, then add an option in the setup so I can turn it off. How hard can that be? Hard for those of us that didn't write this and so get completely lost stepping it with 1-character variables to help keep track of where we are, or we'd have done it ourselves already. It's NOT a requirement of switching an object to richedit mode; this I know.
No argument that P tags are vital, but here's my scenario: one of the things I'm building in my current CMS is a FAQ page. The FAQ "Questions" are short enough that I intend to use them as the URL string in my replacement URL code, so that it will index better (I'm replacing spaces with underscores). But my users also want to be able to do simple formatting of the question (bold, italic, etc). But at the end of the day, for this application, I'm tickled pink to save this string in my FAQ record as a Question: "What is the <b>current</b> rate of pay?" I don't need to save, nor do I want to save, "<p>What is the <b>current</b> rate of pay?"
Why should your software force me to strip that pair of tags, thereby inducing me to both write unnecessary code and waste useless server processor cycles, every time I need to clean this string?
This is the kind of stuff that makes me crazy, and speaking from experience, it's the kind of attitude that drives customers away. I'm just saying.