Is smith machine ok for squatting?

When a regular free weight barbell is used, there are many planes in which the BB can move (up, down, sideways to the left or right, forward, backward). For this reason the person has to stabilize the bar as it moves up and down. The bar should also be moving up and down over the base of support, the feet.

I do find, however, that the problem with a smith machine is that it locks the bar into an up/down path and so if the person's form is not good, it can cause injury to their knee or back.

But it does allow you to place your feet farther forward for when you want to bring the hamstrings in more so. And people can add more weight to a smith machine and progressively increasing your weights over time is always good.

Others are less fearful when the BB is in a fixed up/down movement and need not be balanced as with a free moving

BB. Everyone should feel safe and comfortable at the gym.

The smith machine is NOT to be shunned or laughed at!!

So, should you avoid it, NO.