The real questions are:
1/ Who branded these "Pros", "Pros"? Their Mums? Putting a video on YT and getting 100,000 hits doesn't automagically entitle you to use "Pro" status, it just means you have the skills it takes to make content.
The definition is that if you get paid for your work or make your living from it you are a "Pro" - if you don't make any money or your living you are an "amateur."
A professional golfer gets paid to golf, an amateur golfer does not. It is fairly straightforward.
2/ How can there be THIS many real professional video editors out there? I can call myself a "Pro" out of the blue - doesn't make me one.
You are right, calling yourself a pro doesn't make you one - and by that logic, Final Cut Pro X isn't a professional app just because it has the word "pro" in it's name. Pro would mean it is for people who get paid using the software, so by definition it is not for the casual or amateur user. That is one issue why people are angry they co-opted the name pro. 'Final Cut Home X' might have worked as a name, 'Final Cut Single User X,' or 'iMovie Pro X' - any of these names and there would be no controversy!
Finally the argument is that it is ALL new - well, ok, so use a new name for it then!