Objects to word choice rather than topic at hand

In an argument in which Speaker A objects to a metaphor used by Speaker B rather than to address the argument’s topic, which logical fallacy is being used? Red herring? Ad hominem? Speaker B objected to a government policy of removing children from immigrant parents and sequestering them in camps; she referred to them as “concentration camps.” Speaker A decried her use of language/comparison as “ignorant and offensive.” Was this a logical fallacy? Thank you.

This has been a hot issue ever since Congresswoman Alexandria Ocasio-Cortez brought it up. Not sure that's a fallacy, but there are logical questions here:

1. "Concentration camp" is a loaded term.
2. "Concentration camp" and "death camp" are different kinds of camps.
3. Objecting to the term is a diversion tactic, but loaded terms do often make people defensive, so what do you expect?
4. Calling someone "ignorant" and "offensive" is indeed ad hominem argument.

Rather than a logical issue, this is more a question of semantics.

More details need to be known before an accurate assessment can be made. Speaker A's objection to the metaphor of speaker B does not immediately make speaker A guilty of a fallacy. The use of the term "concentration camp" is certainly highly emotionally charged (and can potentially be an argument by emotive language<> fallacy), and it is perfectly legitimate for speaker A to briefly divert from the topic to address the word choice of speaker B and try to defuse the negative connotations speaker B has assigned to the case of speaker A if they feel that the word choices are unfairly presenting the case as evil or nazi when it is not. However, if all speaker A did was dwell on semantics and never returned to the main issue to defend his/her case, then he/she would be guilty of a red herring<>.
Regarding speaker A's reaction of accusing the word usage of speaker B of being ignorant and offensive, there are still things to be known before saying that's a fallacy. Insults and accusatory terms by themselves do NOT qualify as an ad hom fallacy UNLESS they are used in an argument to conclude the falsity or invalidity of a(n) claim/argument merely by insulting the person making the claim/argument. So if speaker A's implied argument was "Your objection to the policy is not valid because your word usage is ignorant and offensive," then that's definitely an ad hom abusive. If speaker A was just merely stating his opinion regarding the word usage of speaker B, then there isn't a fallacy but a mere opinion.

Definition of concentration camp

: a place where large numbers of people (such as prisoners of war, political prisoners, refugees, or the members of an ethnic or religious minority) are detained or confined under armed guard —used especially in reference to camps created by the Nazis in World War II for the internment and persecution of Jews and other prisoners.

"For three years, his family lived in what was essentially a concentration camp, ringed with barbed wire, with about 9,000 other Japanese-Americans.
— Jon Gertner, WIRED, "The Top Secret Cold War Project That Pulled Climate Science From the Ice," 12 June 2019"

Speaker B : American detention camps along the border are Concentration Camps
Speaker A: Concentration Camps only pertain to German Concentration Camps in WW11
Therefore: American Detention camps cannot by definition be called Concentration Camps

Obviously this is a:

Subjectivist Fallacy
(also known as: relativist fallacy)

Description: Claiming something is true for one person, but not for someone else when, in fact, it is true for everyone (objective) as demonstrated by empirical evidence.

Logical Form:

Person 1 claims that Y is true.

Person 2 claims that Y is true for some people, but not for everyone (even though empirical evidence demonstrates otherwise).

(1) Your argument concludes that p is objectively true.
(2) P is subjective.
Therefore:
(3) Your argument fails.

It should be clear Speaker A is committing a Subjectivist Fallacy.