There's not a lot of meat on the exploration rules in 5e (AiME notwithstanding).
There seems to be a decent level of creativity amongst DMs here to make up for that lack, making exploration in their games fun.
Both statements are true. One can't use the second statement to refute the first one, though.
So when someone says "The game is missing X," and the response is "Make X yourself," well...yeah. I have to. Because the game I purchased doesn't address it adequately.
And I guess that is what some people are put off by? They bought a game, and the game is supposed to provide adequate rules for X. When it doesn't, it's ok to be put off by that. For an RPG, since you aren't buying a board, minis, etc...you really are just buying a ruleset. That's it. Nothing else (the minis are extra, but hardly required). So if it's lacking, it can be annoying. Surely people here have had a similar experience with a board game or somesuch? House rules for board games can be fun, but we'd never look at them and say "Thank goodness this scenario that's supposed to be part of the game has such poorly designed rules we made our own."
As for the actual issue of exploration, in previous versions of the game, one could interact with the environment and depending on how well you did, there could be consequences that were meaningful (loss of healing surges in a fail forward 4e skill challenge, for example.) 5e has some consequences...but they are too easily avoided or dealt with.* I suppose if you suffered a level or two of exhaustion and then immediately had a fight, it would matter; multiple exhaustion levels are hard to deal with, IIRC.
Someone further back suggested the better division was Journeys, Battles, and Downtime, and that makes good logical sense to me (and again, AiME does this).
It seems like exploration in 5e is really more about highlighting how cool some PCs are; let the ranger player describe how he guides the party through the dense forest, gathering berries, etc. If she does a particularly good job, give her inspiration. Let the Outlander go off on how he guided them through the Orc Mountains, avoiding patrols, etc. If Chaosmancer is right and most of the options are actual inevitable situations, let the players take over the descriptions and have their PCs shine. Then, do the same when the wizard hits the library looking for information, the rogue when she interrogates her underworld contacts, etc. Exploration pillar = PC shine time. Why not?
*I suppose tracking is an exploration pillar activity that has potentially serious consequences?