PBA: That Gemara has 2 Leshonos. According to one Lashon it was clearly a Geder and a Chumra. According to the other there is what to discuss. I think the general assumption is Lekula in such a case, but I’ve never really looked into that in such huge detail.
Whether or not they got a P’sak might not change their intentions, but it might change how we regard them. If they have a legitimate P’sak Lekula, even if they want to be Ma’avir Al Das, presumably the Chillul Hashem aspect goes away, and that is what makes it Yeihareh V’al Ya’avor anyway according to the Rambam (it is not entirely clear to what extent the other Rishonim disagree with that position).
But you are very right. Regardless of if this is actually Yeihareg V’al Ya’avor, since the Israeli army wouldn’t actually kill you for not attending then someone who holds it’s actually Kol Ishah would not be able to attend. (Unless you want to call it a Safek Pikuach Nefesh because in theory the army could call that treason, which is a death penalty offense. I would assume that that is a far too Rachok of a Safek to even qualify. Even if the Israeli army could make that case, there is no way on Earth they actually would.)