The issue of skill required to use certain decks is very vague. An unskilled player can use a good deck and make mistakes but still get lucky and win, while a skilled player can wind up with a terrible hand with the same deck and lose.
Skill is not entirely detrrmined by what deck you run, but rather by how you construct your deck, and how you utilize your cards in-game.
This being said there are 2 reasons why people don't like decks such as burn and exodia.
1. They feel it's easy to go into auto-pilot for the strategy, which is silly because the same could be suggested for most combos of meta decks. The fact is, the more skilled a person is, the better they should be able to utilize their cards in-game.
2. They themselves are skill-less and are too lazy or ignorant to make sure their own decks can deal with those types of strategies, be it by maining certain cards or by having a properly built side deck.