ubiquitin: Anyone can create any personal or group memorial or commemoration. Many people celebrate their wedding anniversary. Others may mark every year the date they were rescued from kidnappers. Nothing wrong with any of that. But they aren’t a Jewry-wide day. A Jewry-wide day can only be instituted by Chazal. And it is unreasonable to expect all of Jewry to recognize a day some group of laymen, especially laymen who have no love for the Torah, institute.
As far as the two reasons you outlined in your first post above, I generally agree with them. (Though not your analysis that we feel excluded/slighted due to our non-participation. There was no point or benefit in the armed resistance and we are glad we didn’t participate.)
That being said, even if the institutors of this day did not choose it to commemorate (and date it to) the armed resistance and did not use it to signify that they believe the geulah has already come, we still would not participate in it. That is because we already have Tisha B’Av for this purpose and use it for just that.