What is the proper name of the "knowledge fallacy"? Or "generalisation fallacy" and "rhetoric fallacy"?

Basically, it goes like this (in two examples), because I seen it pop up on gun control threads about the debate of guns.

First example goes like this:

Person A says he is for gun control.
Person B asks Person A if he knows a specific detail about guns.
Person A says no, then Person B asks Person A a specific detail about a gun.
Person A doesn't know, then Person B says that Person A is not qualified to talk about gun control and should stay out of the debate.

The second example goes like this:

Group A supports gun control.
Group B argues Group A is mostly compromised of teenagers.
Group B then argues that teenagers, in general, mostly do not know anything about guns.
Therefore, Group B says that Group A, compromised of teenagers, does not know anything about guns and should stay out of the gun debate.

On the subject of the rhetoric fallacy, this is how I saw it go down (also in two examples):

First example:

Group V uses rhetoric to prove their point in a debate.
Group Z points out that the rhetoric Group V is similar or the same as Famous Person X in their speech.
Famous Person X is known for their rhetoric being used to justify a fallacy.
Therefore, Group Z dismisses Group V's point based on the similar rhetoric used by Famous Person X.

Second example:

Group V uses a sentence to argue a point.
Group Z accuses Group V of a logical fallacy.
Group Z then dismisses Group V's point out of hand.

I dunno what are the fallacies for this, but it is similar to what someone told me as the "stfu if you don't know a entire book about guns" for the first one and the latter it is similar to "you used a fallacy, so your point is invalid".