Garen is an incredibly straight forward champion. If he knows what he is doing he knows exactly how every fight and trade will end up before he goes in. The same exact thing can be said about laning against him, if you understand him you know exactly how everything will turn out.
He has been like this since season 1 at a minimum, and his kit has not changed so much that very early guides to beating him would be unusable. There are roughly seven years of useful guides out there for you to use if you can't seem to deal with him.
I'm biased on this matter, since I'm a Garen main and have played him since I started back in season 1. I'm not biased because I want him to be good, I'm biased because I've known how to beat him for years and have both put that into practice against him and learned it the hard way by having others beat me. He can't make plays and only gets ahead if you make mistakes and let him, so if you really think armor does nothing and him building squishy means the lane is over you have more than a few things to learn.
If you have any actual questions I'd be happy to try and help, but if you're just going to vent about him you're going to have to put up with me venting as well.