I find it weird that that list is titled "BASIC dialects" but then lists implementations. There are a couple dozen implementations of the Microsoft BASIC dialect (and another half dozen BASICA), for instance.
Edit: And the wikipedia page clusters them nicely in a separate group, what more could you ask for.
https://en.wikipedia.org/wiki/Microsoft_BASIC
And clicking any of those will list them as a "Microsoft BASIC" dialect. This list lists them independently as their own dialects. I just found that slightly humorous. It wasn't intended as anything more.
If you want to be serious about it, I agree with you. Each of those is different enough that they certainly could be considered their own languages and "Microsoft BASIC" a superset (akin to Pascal, Ada, Oberon, Modula, etc all being "Wirth-languages") vs "dialect".