It’s not quite that simple. To be clear, the argument being proposed by his lawyers is that he is not an “officer of the United States” so it doesn’t apply to him.
Basically, there’s legal precedent that elected officials aren’t officers of the US because they are elected and not hired. Add to that the sheer number of commas, “and”s, and “or”s, that it can get legally murky.
NB: Not a lawyer. Read about the above on Mastadon from a legal scholar. Will see if I can find the link.
The argument I’ve seen is that the condition part of the clause (insurrection) by language only applies to the bit after “who, having previously…”
Basically, the argument goes “It says you can’t be President or Vice President if you did insurrection while an officer of the US”—but it doesn’t say you can’t be President if you did insurrection while president of the US.
To be clear: I think it’s fucking idiotic and against the spirit of the law—but I’m no lawyer/legal expert.