I believe that's an exaggeration that's been passed around. I think people noticed that the heavier (200gr.) projectiles produced a greater recoil and assumed that this greater recoil could damage the gun in some way. In time, I'm sure it could, but for a civilian owned rifle, I don't think it will ever be a problem. I don't make it a point to shoot the heavier stuff anyway, but I'm not afraid to try it.
The 183gr. Yugo had a slightly heavier recoil than th 147/148gr. stuff I've shot in the past, but the 174gr. Hungarian had no noticeable difference. The 203gr. Silver Bear SPs that I shot a single mag through it with had much heavier recoil, but like I said it was just one mag.
I don't think it would hurt it if you fed it a steady diet of the 174gr. ammo, but I wouldn't go much heavier for an everyday load.