No problem

Most people hate on machines, so keep that in mind

Your muscle is only going to get bigger if you push it

If I could bicep curl 100lbs on the bicep machine, my bicep isn't going to grow until I can bicep curl 100lbs+ in free weights. Bicep curling free weights of 75lb is working out other muscles in the arm but not going to make my bicep any bigger because it can already curl 100lb. I wouldn't be able to curl 80lbs not because of my bicep but because of the other muscles required for the free weight.

The debatable part is that you shouldn't be able to bicep curl 100lb and not be able to pick up a 50lb dumbell and curl it with free weights. If you're spending your time working out, doing a complex exercise can be more beneficial. Also you're working your stabilizer muscles which you can't on a machine.

Machines are a tool, and you have to be smart with them.