"The unauthorized practice of a profession is prohibited by state laws."

"unauthorized practice of a profession" is not the same as offering an occasional comment on a blog. It's pretending to be a lawyer or acting in a way a lawyer would or charging for it.

For one thing it would be seen as de minimis not to mention the fact that there is no compensation for the service.

Think of it this way. You may need a license to have an office and offer therapy and pass some tests. But do you know of anyone who ever got charged with impersonating a social worker by offering advice for free to a friend?