That is some terrible advice right there. The frame matters, way more than what rear derailleur comes with it. First of all, if the frame don't fit the bike won't be enjoyed. It doesn't matter if it has the best fork and parts in the world.
Second, put this guy on a dirt jumper and it is going to suck for him. And if he goes full suspension, then the frame is key.
For someone riding casually on pavement a suspension fork won't be a problem. Even without a lockout. And the weight won't be such a big deal either.

For what the OP is looking for, a hardtail in the $1000-1500 range should work. On that price range you should be getting air suspension, maybe even a lockout (which stops the fork from moving when riding on smooth surfaces) It won't be light, but it should be fine to get started.