The moment someone says something like that to me tells me one thing about them immediately. They haven't read the Brothers Grimm, Hans Christian Anderson etc as if they had, they would never describe the tales as twee!
There is no way Disney could have made The Little Mermaid exactly as per the original story. It would've been given an 18 certificate!
I love fairytales because they're timeless and there is often a moral to them (without being preachy and I have sat through enough sermons to know this kind of thing doesn't work. What you do want is something that makes you think and this is often a talk/sermon which is to the point and where you feel not one word has been wasted).
Fairytales are economical with words but also conjure up (literally!) images that stay with you usually for life. I can still see images of Cinderella etc from the Disney films I haven't watched in decades.
I think my favourite thing about fairytales is you know justice will be dealt out to the wicked. There's no mucking about. You know they're going to come to a rough end and that the injustices will be put right. Then I watch the news and some horror is being perpetuated and I think.... well you can guess the rest I suspect!