And yeah, a doctor should be able to give tax advice and legal advice. Foo on you if you take it. Only a liberal would think people are too stupid to know better.
Doctors are regulated in all sorts of ways. They may not practice law etc. They are licensed by the state to be doctors and the state can tell them what that license allows them to do.
You may not like it that doctors are licensed, but reasonable people see the need. Only an anarchist would think doctors shouldn't be regulated.