The great thing about BOTM is that there are no guidelines or criteria (apart from a simple one to gain entry every other month) or anything. Enter a bike and vote for one.
If you want to use your own criteria for voting then that's cool, no problem.
The way it is run means we get to see loads of different bikes put in the spotlight and shown off by their very proud owners.
Sometimes one wins because it is rare or a one-off or an ex-team bike, but on the other hand sometimes we see a winner which is quirky, or simply an amazing back-from-the-dead resto, or a bike with personal history or patina. It doesn't have to be the high-end stuff and BOTM is all the better for it, it's all inclusive.
You may not like or understand why people vote for a particular bike, but that's cool, we all like different things. There is no definitive "best" retro bike, it's all subjective.
You could look at it as a qualifier for BOTY, where the truly outstanding win, and deservedly so.
Long live BOTM!