I think that just as with ISPs people become irate when they feel there's been a bait-and-switch. Had they very loudly advertised the subscription as limited to their harness up front with a note about maximum token use people presumably wouldn't feel cheated. Whereas they seem to be pulling a "pray I don't alter it further" for the second time now.

You don't get to sell a subscription described primarily as being for some quantity of X and then change the terms every time people find creative ways to use the stream of X they believe themselves to have purchased from you. People thought they were purchasing in bulk.