Incorrect, and this is ad hominem.
>>>>> impression of a deep understanding of
Who is being referred to? Who is being characterized? Certainly not no one. Thus, ad hominem attack.
> you're free to commit logical fallacies as much as you want, but the moment someone else does, you halt all discussion and just shout "fallacy!"
This is ad hominem. But it is also a straw man masquerading as tu quoque.
