Lol, the thing that gets me about this is...he still left a map behind.

Even if it took a convoluted way of piecing it together and he obviously made it difficult for everyone...there was still a map. That's not exactly burning your bridges
all the way. I think the Macguffin of the map is what made a lot of fans - at least in my circles - think that he'd left that as a breadcrumb trail for a reason, so that "when the time was right," someone (or a group of someones) would pursue and locate him to bring him out of exile, and he would have been waiting for it all along.
What's hilarious for me is that even Legends EU did this -
Black Fleet Crisis Luke pretty much did the same thing. Holed himself up in one of his dad's old castles - rebuilt by the Force lolz - so he could have some alone time to mope. He didn't even want to train his sister's kids. Of course it all got resolved by the end of the series. I have to continuously remind myself there's actually quite a lot of material in Legends that either inadvertently or perhaps deliberately got mined and remixed in a blender for Disney!canon. Legends EU was plenty questionable itself.
And, well...going into exile due to a sense of failure and bitterness was...also seemingly selfish. Either way he'd put himself out of reach of his family and comrades. They might have been more understanding if he'd done so for reasons that were ultimately intended to have some sort of purposeful outcome (meaning, even if they got upset at him vanishing at first, they'd forgive him later after finding out what happened).
Plus, when you're Luke Kriffing Skywalker...frankly, I think that level of crushing responsibility and incredible lifelong accomplishment deserves some "me time" if he felt like it. I didn't blow up a Death Star and save my evil dad and I know
I deserve some "me time" on occasion too.

We all do, amirite?
I might have been cool with that if he'd been less of a salty jerk about it.
I get that there's a time and a place to show a character being disillusioned and brought out of that despair; I know some people found Luke's arc in TLJ to be personally inspirational, and while I don't see that at all for myself, you do you boo-boo. But the degree of his bitterness rung way too harsh for the man we grew up seeing in the OT, and it stung even more when it became painfully clear that the OT characters were being dragged through the mud for the sake of having a new trilogy and a new conflict that didn't necessarily have to exist in the first place.
Luke was already broken in the OT. He was shattered but managed to hold himself together and pull through victoriously. Considering the crucible he'd already been through, we figured he could weather another deep personal tragedy with...a little more grace. I'll leave it at that.