The journey simply doesn't take place as quickly as depicted. It's really jarring. White Walkers existing has nothing to do with this, that's an established idea. Fiction has rules, just because a dragon exists doesn't mean that logic be damned. I hate that argument so much. A world where Superman exists should have NO basis of logic at all...because Superman is there? Dragons and white walkers are established here, they're a part of this world.
The reason people are highlighting this fact, is because the show was once REALLY good at being an immersive world where things like that were fully taken into account. I get that we are running out of time, but it's very jarring.
You can 100% criticize a show and still enjoy it. I love Game of Thrones a hella lot, despite these recent flaws- but they are flaws.