Because an OPTION is present? Hogwash AND nonsense. Critics are smarter than that. 'Fans' won't use it for the most part.
Over time, options and/or changes to modes like that could create a shift in the way games are reviewed or experienced. You could argue that shift would be a good thing overall, but there are also good arguments in favor of the status quo (in that
specific respect, not necessarily status quo overall).
You can say critics are smarter than that
now, but if we see a slowly shifting paradigm in the way games are designed to accommodate less interaction, more passive consumption if desired, self-imposed difficulty starting to become a thing of the past, it's absolutely possible for industry criticism to change, as well as game design itself.
Who knows? If all games adopted boss fight skipping overnight, maybe devs would lean toward making harder bosses because they know people can just skip them if they're too hard and want to offer a challenge to the remaining players. Maybe devs would lean toward easier bosses because they know people might just skip them if they're too hard, and want that content to be experienced regardless. Or maybe they would make
fewer bosses because they know that their hard work on those bosses would often just go to waste - we already see this happening via stats on game completion, all the money is spent in the first few levels because that's all 50% of players ever see. Not necessarily even due to difficulty, just people losing interest. That's also why there's been a gradual reduction in side quests and optional content, it's seen as a waste of time and money on the 5% of players that will actually do it.
Options absolutely impact the rest of the game design, whether you can see it or not.
