These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Values Resonance: A sympathetic portrayal of gays may seem commonplace today, but the story was originally written in 1913.
Doesn't hurt that Forster was himself a closeted homosexual.
And let's not forget that he gave Maurice a happy romantic ending that didn't involve him or his love interest dying, something that still isn't quite as common as it should be nowadays.
The fact that Maurice thinks of sex as "sharing" is surprisingly modern as well, given that even today sex is viewed as some sort of commodity transaction (particularly with regard to the whole virginity concept) rather than a shared experience.