Yeah it was schlocky b-movie stuff overall to be sure. I definitely had a soft spot for him as a kid, and as others have said it’s pretty disappointing that he’s turned out to be such a cockwomble.
I was wrong in that it has been used to describe right wing extremists but it does originate with the idea that these people would happily hop in a tank and crush any dissent. I realize I was very vague
In my mind, it made sense that anyone willing to use force (eg, a tank) to impose their violent ideology is a tankie.
Sorbo has been a reactionary shit going back to his early career, but he didn't really let the freak flag fly until he stopped landing roles in the mid-'00s. He's got a whole line of really cringey anti-Atheism movies (check out the "God's Not Dead" series trails) and he's been dipping his toe into the MAGA sphere since Trump took office.