The problem is, the other side definitely does not play by the rules and has no intention to. Why should we "police our side" and weaken ourselves? The endless purity testing on the progressive side of politics is a large part of why the far-right is so damn powerful worldwide.
Ironically purity testing is something we should police.
We police ourselves because it makes us look better to moderates and defectors as the other side fails to fulfill its promises.
If the other side doesn’t police themselves, it’s their loss, because they’ll alienate fence-sitters and (mispredicting due to groupthink) fail even harder.
The problem is, the other side definitely does not play by the rules and has no intention to. Why should we "police our side" and weaken ourselves? The endless purity testing on the progressive side of politics is a large part of why the far-right is so damn powerful worldwide.