I think the argument is that if people aren't required to be in the union then people can free ride on the union's efforts without paying dues.
If you want to dodge the free ride then have the dues go to a non political spending charity of your choice provided it is local, may I suggest children's healthcare hospitals
[1] https://en.wikipedia.org/wiki/Communications_Workers_of_Amer...
This isn't true.
"far too many unions spend inordinate amounts of money on political activities instead of their own membership"
If you believe that, then start getting involved in your union's leadership and change it.
" then top it off with all the bureaucratic bloat and high paid leadership"
As opposed to the leanness and crappily paid leadership of the company?