You Say Tomato. I Say WTF is the Difference Between Roma and Plum?

One of the many reasons I hate cooking is because of things like roma vs. plum tomatoes.

I had a recipe call for one (I can't remember which one now) and I got to the store and it didn't have 'em, only the other kind. And I stood there wondering if it would make a difference.

I mentioned this in passing to my mother and she was like "there's no difference between roma and plum."

So WHY are there different names then? I mean, it's not like they're BRAND names describing the same thing (e.g., Tylenol is a the brand name for the generic acetaminophen).

If there's no difference, just pick a name and be done with it.

I googled this, of course. The best I can figure out is roma is a type of plum tomato. So plum is the umbrella category and roma comes underneath it. (So do cherry tomatoes, apparently.)

Fine.

BUT WHY ARE THERE TWO SECTIONS IN MY LOCAL MARKET BASKET? One says "roma" and the other says "plum," which is what leads me to think they are different?

I found this video on YouTube, and it's not particularly helpful, but I'd recently been wondering what happened to the group Anonymous (remember them?) because we could use their help right now with uncovering some of the fuckery going on in the US and, apparently, here's what they've devolved into...

Doesn't it sound like their classic disembodied voice?

WHAT IS HAPPENING???