I do have to agree, it's almost insulting to the rest of us. I'm sure the guy meant it with no ill intent, but it still is a touch insulting.
He misses the entire point of it. It's things like this that make me dislike the word "waifu", since it's associated with "favourite girl of the season".
You shouldn't speak for others, either. I can't quite say I'm offended since I'm used to this crap now, but I'm not exactly pleased. He even has the nerve to say he loves them all equally, here, where some of us would throw away absolutely everything for a brief moment with whom we love. They mean everything to us, and he spits on that, on our lives, on us. Perhaps he didn't mean it, but it still stands like that.