One really cannot judge all "ecchi fanservice" as a wholesale thing.
I frequently object to many unnecessary and gratuitous ecchi scenes, but I also enjoy a lot of fanservice too, to the point where some people call me "Pervwing", because I'm talking about Hiromi from True Tears doing splits when they're trying to tell me about how great of a romance it is.
Still, I think there's a difference between objectification and simply showing off the beauty of a character. For example, Rinne no Lagrange, often will have quite a few ass shots. But I usually would go "Lan's ass is fairly attractive" rather than "ZOMG ASS ON THE SCREEN". The former is more admiring the character design and sexiness, the later is just well... finding a piece of meat to have fantasies about.
When the fanservice overrides the character themselves, that is where the problem comes in.
Take the extreme example-- hentai. Most of it isn't arousing at all. Some because it is gross, but others just because it's too blatant and silly. So there's a limit to what you can shove into people's faces before they'll get annoyed.
Also, visual quality matters too! At least have good fanservice (Inu x Boku SS)