I generalize a lot, although I'd prefer to refer to it being selective with what I choose to spend my free time reading. While there have been times where I've gone back to give something that I've filtered out another shot, I have to say, I haven't once regretted my initial decision to toss something out.
In a lot of cases, it's not that someone is close-minded. It's called being smart and using your time wisely by understanding what you like to read. Would you prefer it if people who knew they weren't going to like your story went ahead and read it anyway, and then followed up leaving a huge critical review about how much they hated it for being a harem even though it was a clearly labeled harem fic? It's not just about the skill of the writer. Broader themes, world views (relationships, gender equality, preferred genres) can all play a part in whether or not someone is going to enjoy a story. Someone being an awesome writer isn't going to override a reader not wanting to read something that contains content they find abhorrent. There are plenty of other stories out there for them to read and they are under no obligation to give every story out there a chance.
Readers owe authors nothing. It's up to the author to sell their product.