I know this isn't an acrylic vs glass thread but...
I've owned acrylic and glass for more years than many members here were alive and the reason I prefer acrylic is because I'paranoid of busting a seam which has happened to me and I want my tanks to last a lifetime.
No, all is due to improper care
I used to maintain aquariums and heard the same thing from a customer. Of course, he put the tank on a metal stand with 1" support along the edges and he proceeded to clean it with steel wool
What? Anything made improperly is trash. Make an acrylic tank with too thin acrylic or put it on a stand made for glass-only and sure, maybe it will warp. Make a glass tank too thin and watch what happens when your 5 year-old bumps his head on it!
Small glass tanks cost less than small acrylic tanks. Big glass tank cost more than big acrylic tanks.