Except no one minded when Texas Democrats made a habit of this, and would be outraged if Tennessee Republicans adopted the same approach.
I can't really blame people for supporting, say, a walkout to block a gerrymander or voter suppression laws, but doing it for other basic policy on a regular basis? You can't govern like that. This is basically a tyranny of the minority situation, where they are trying to exert power they aren't entitled to.
In Oregon's case, the voters themselves approved the amendment in an effort to stop this behavior. Granted, I have always thought this was a stupid fix and they should have directly addressed the quorum rule, but it is what it is and for now, Republicans really don't have a leg to stand on. They knew what the deal was. They over-played their hand on walkouts.
The ballot measure was funny but if the last petitioners were trying to preserve room for short protests, it didn't stop the ORGOP from continuing to block quorums now that safe-seaters see they can just cycle through willing family members every other cycle, so it obviously didn't work & the next ballot initiative needs to set the quorum at 50%. Hopefully the next initiative amendment's campaign arguments need not amount to any more than "We did the absence amendment to try leveraging the ORGOP into stopping their constant walkouts, but it didn't work, so now we need to solve the problem outright by just ending the 2/3rds-quorum altogether for the Legislature to be able to function" to win the ratification vote.