How can he sit on a log when before he was just kinda floating? All these answers and more in the next exciting chapter of just try and relax it doesn’t make any difference.
somethings need to be explained somethings don’t. When force ghosts can now do something they couldn’t do before, it requires an explanation. If in the next movie Han Solo(in the flesh, not a ghost) suddenly walks into a room, don’t you think that would require an explanation.
So, when things aren’t explained why force ghosts can suddenly do something that they couldn’t do before, like interact with their surroundings, in the OT, then that’s fine because you say it doesn’t need to be explained. But when they do something they didn’t do before and it isn’t explained in The Last Jedi, a film you don’t like, then it is bad because it requires an explanation, even though it doesn’t?
I agreed that why Obiwan didn’t warn Leia is a good question.
the minor interaction with surroundings we see in ROTJ don’t matter near as much as finding out that force ghost Obiwan and Yoda maybe could have appeared before the Emperor and Vader and zapped them.
I will however agree with you that one tends to focus more on plot holes and continuity errors and whatnot in movies they don’t like as compared to movies they do like.