Based on your example sentence, the following word seems to be more appropriate than those already posted:

technicality, noun:
something technical, especially a detail meaningful only to a specialist (Merriam Webster)

As in:

That's a technicality, you're focusing on a technicality.

As an example, imagine an argument between Person A and Person B. Person A makes a point, using an example of an incident which is relevant to the subject of the argument. When describing the incident, they mentioned that it occurred at 8pm. Rather than responding with a counterpoint, Person B notes that the incident in fact occurred at 7pm.

While Person B is technically correct, the time the incident occurred has no bearing on the validity of Person A's point. In this case, Person B would be focusing on a technicality, and Person A might respond with the sentence above.

Based on your example sentence, the following word seems appropriate:

technicality, noun:
something technical, especially a detail meaningful only to a specialist (Merriam Webster)

As in:

That's a technicality, you're focusing on a technicality.

As an example, imagine an argument between Person A and Person B. Person A makes a point, using an example of an incident which is relevant to the subject of the argument. When describing the incident, they mentioned that it occurred at 8pm. Rather than responding with a counterpoint, Person B notes that the incident in fact occurred at 7pm.

While Person B is technically correct, the time the incident occurred has no bearing on the validity of Person A's point. In this case, Person B would be focusing on a technicality, and Person A might respond with the sentence above.

Based on your example sentence, the following word seems to be more appropriate than those already posted:

technicality, noun: something technical, especially a detail meaningful only to a specialist (Merriam Webster)

as in: "that's a technicality, you're focusing on a technicality."

As an example, imagine an argument between Person A and Person B. Person A makes a point, using an example of an incident which is relevant to the subject of the argument. When describing the incident, they mentioned that it occurred at 8pm. Rather than responding with a counterpoint, Person B notes that the incident in fact occurred at 7pm.

While Person B is technically correct, the time the incident occurred has no bearing on the validity of Person A's point. In this case, Person B would be focusing on a technicality, and Person A might respond with the sentence above.

Based on your example sentence, the following word seems to be more appropriate than those already posted:

technicality, noun:
something technical, especially a detail meaningful only to a specialist (Merriam Webster)

As in:

That's a technicality, you're focusing on a technicality.

As an example, imagine an argument between Person A and Person B. Person A makes a point, using an example of an incident which is relevant to the subject of the argument. When describing the incident, they mentioned that it occurred at 8pm. Rather than responding with a counterpoint, Person B notes that the incident in fact occurred at 7pm.

While Person B is technically correct, the time the incident occurred has no bearing on the validity of Person A's point. In this case, Person B would be focusing on a technicality, and Person A might respond with the sentence above.