It is of no importance whether any one particular person or group of persons believe the "truths" to be "self evident". The Declaration states "WE hold these truths ..." (emphasis on WE).
In other words - the signatories to the Delcaration were stating quite clearly that THEY believed that the truths were unable to be contradicted and thus, for them, something worth fighting for!
Most people forget what the Declaration really was - it was the justification of the signatories as to WHY they sought independence from England - in hopes that other nations (mostly France) would come to thier aid.
Thanks for the very nicely stated correction to a basic premise of my statement. You are right, of course.
However.
If the truths "WE hold" are not self-evident to a majority of voters in a democracy (or even a Republic such as we are in the process of transitioning away from), then it's inevitable that the freedoms we've enjoyed under our Constitution will pass away.