Load of crap. Look up the degree of utilization of mail-in voting among the constituents of both Parties. It's roughly 50-50
It makes sense for those in the military, overseas in particular. Got a problem with those people? Want to fly them home to stand in line?
Makes sense for the disabled and for those who simply don't want to get up too early or to stand in line on one fucking day.
Badly mismanaged pandemic responses also make it, handy.
Bottom line, no one had any problem either with mail in voting, absentee voting or early voting until the authoritarian, orange, ass-hat started with his 'if I don't win then the election is fixed' delusion, which morphed into his stop the steal bullshit, which then morphed into his incitement of 'The Insurrection of the Morons'.
By the way, attempting to overturn a legitimate election is as dictatorial as it comes.