I agree it's probably true, but he hasn't been convinced of insurrection (yet), has he? The sixth amendment to the Constitution guarantees a fair trial, no?
So the sitting government decided their opponent is guilty of "The act or an instance of open revolt against civil authority or a constituted government", and then told you and everyone else you're not allowed to vote for him. Could that not be applied to all opposition?
That's not concerning? What if it's switched next time?
The government also says I can't vote for Arnold Schwarzenegger for president, because he's constitutionally ineligible for that office. The reasons someone can be ineligible for the presidency seem to be fair, and accurately enforcing them isn't a slippery slope.
The 14th amendment section 3 lays out that someone who takes an oath of office and then engages in insurrection is ineligible to hold office unless Congress removes that ineligibility, and this seems to be what Trump has done.
If anything, if he's truly ineligible, not removing him from ballots is the thing that should be concerning. Maybe SCOTUS will deem him actually eligible, but not starting that process seems to be the wrong thing to do if you believe he's actually ineligible.