Nobody has the same waifu as me. Hell, if I posted a picture of her right now, I imagine a solid 95% of people here wouldn't recognize her, and well over 99% wouldn't know her name.
The problem is that real waifus aren't actually eternal. I could keep pretending that thinking about her makes my heart ache, but after her story ends, all you have to go on are your personal understanding of the character and some cute images, and true emotion can only be sustained for so long by such things.
People who sit around all day and post about their "waifus" are probably not in love. If they are, it's early in the relationship, and maybe they're just doing it because they think it's the norm. But for people who claim to have waifus for years, they're either significantly mentally ill, or just whoring her out for attention. The waifu just becomes a tripcode analogue, a way to differentiate yourself from the anon masses and blog about your life in a "safe space".
Feelings fade. It's only natural, and in a real relationship, you eventually just become good friends with the person you're dating or married to. With a waifu, there is no personal connection, so you can't really bridge that gap at any point. I still think my ex-waifu is cute, still the cutest girl around. But the spark isn't there anymore. I don't feel guilty when I look at other girls, I don't daydream about her. She's not my wallpaper anymore, and I only look back on my picture folder of her every year or two as a form of reminiscence. There's no relationship left, where there used to be an idealised one-sided one.
So basically, who the fuck cares? You probably haven't found a waifu anyway. And if you have, it's not going to last that long. Why give a shit about other people?