Staying together for the kids can be far, far worse for the children than a good divorce. Especially if you "stay together for the kids" but dad's method of coping with it is escapism from reality with a sex doll, which by itself already sounds somewhat unhealthy. If there's one thing in those comments and "interviews" in common, is that all those men seem to be introducing a real person inside inanimate dolls, replacing human interaction for a controlled, imagined one. I'm no psychologist, but I believe that most, especially now in the high wave of the digital era, warn about the dangers of depending or losing yourself too much in make-do relations instead of real ones.
To me, it's not about being weird or not, but about how incredibly unhealthy it sounds to become a person whose closest relationship is a made-up one by yourself with a doll. A notable exception, I believe, are those cases where the person in question is truly lonely and with not many options, like the elderly. Maybe I'm wrong, but it doesn't look like just a hobby in most of the cases.