It's two different quotes.
Whenhe says "that's not a name I've heard in a long time".Obi-Wan rescues Luke and R2 from the Sand People
When they're talking later he says "a name I haven't gone by since before you were born".
I suppose, depending on your point of view, he might have been called Obi-Wan by other people but he seems to be calling himself Ben, so he hasn't 'gone by' Obi-Wan..?
But that's part of the fun.
Trying to reconcile the universe with it's own 'world-building' is a side-effect of how popular that universe has become - and the fact it's been managed in so far as canon goes, pretty badly.
You can engage or ignore it entirely.
The abuse towards actors is different and should be stamped on from a great height.
I agree to a point, Star wars is full of plot holes, some are amusing and some are obvious flaws but what is annoying (and it's not just with SW) is people are becoming obsessed with finding them as a stick to beat a program with just because they disliked something. It's getting tedious.
I've watched every episode of everything Star Wars bar Bad Batch, read all the EU books and played every Star wars game, the plot holes are literally everywhere but I don't care because its more Star Wars.
But as you mentioned, it's got to the point where its gone beyond differences in opinion over story or plot holes and now actors are being racially abused which is absolutely abhorrent, Ewen McGregor was spot on in calling them no fans of Star Wars.