Appeal to motive

This is a question about the appeal to motive argument aka Ad Hominem (Circumstantial)
Are there 2 kinds appeal to genuine motive and appeal to false motive?

Say a pilot were to say "I think pilots should be paid more"

The other person comes back with "you only say that because you're a pilot..."

In the second example someone says "I don't believe in affirmative action"

The other person comes back with "you're only saying that because you're racist"


So in the first example the person is a pilot and does not deny this, but they deny that their motive is just about wanting more money, the other person isn't accusing that other person of being a pilot. This is not disputed.

In the second example the person saying they don't agree with affirmative action is being accused of being a racist, something which they deny. You think that therefore your motive is you are a *bad thing*.

So is the second example Ad Hominem (Circumstantial) because in the second example their circumstance isn't that they're a racist, they're just being accused of it.

Interesting question.

Your first example, in part, is a display of bulverism The person is assuming that the claim is wrong because of a group the person belongs to. Also implied in the argument is a demonstration of the fallacy you mentioned, the circumstantial ad homenim, as the person is assuming the arguer is biased on the issue because they're a pilot. 

The second example I think is display of the guilt by association fallacy. They are trying to make the arguers position seem untenable by associating it with something that is generally disavowed (racism). While it's almost certainly the case that racists do not believe in affirmative action, it doesn't mean that everyone who doesn't believe in affirmative action is racist. 

These are both examples of bulverism where someone is assumed to be wrong, and the arguer skips to explaining how they came to be wrong (typically using some pseudo-psychoanalysis).

Implicitly they can also fall under ad hominem (circumstantial). A pilot being disposed to desire a higher salary does not mean that paying pilots more is a poor idea; there could be arguments independent the identity of a pilot that justify the higher wage rate.

"you only say that because you're a pilot..." , "you're only saying that because you're racist"

unsubstantiated claim. We do not have enough information to determine if the claim is true or not.