No, you're right. Lawyers are protected by their licensing requirements. However the medical profession does protect itself and is opposed to bringing in many foreign born nurses, medical staff, etc.

Lawyers have that nice shield that is the bar exam, but that is also de facto immigration since only ABA accredited schools qualify. So in one sense you're right, the legal profession does not need to lobby against high skilled immigration. However, the reason they don't need to isn't for any moral reason but rather because they can just lock out immigrants through non-legislative means.