I see this as spite for rejecting the authority’s diktats. Why euthanize if it will die on its own after a possible parent rejection?
Bingo. My guess is that the Park Management interpreted this as a Good Samaritan thwarting Nature’s elimination of this calf, and it was up to them, as self-appointed God-substitutes, to finish the job. Show the stupid public the error of their ways, assert their authority, and kill things gratuitously — government doesn’t get a trifecta every day.
Why doesn’t Park Management have a better plan for such situations (wildlife interactions happen), other than killing the animals?
You see it correctly. The answer to your question is contained in your first statement.
Bison aren't the brightest beasts on the planet, but they are related to cows, most of which would eventually claim their offspring once their milk filled tits started hurting.
Are they going to hunt down and euthanize the mother because she will probably get mastitis?
It “was causing a hazardous situation to approaching cars and people along the roadway,”
The excuse they used to make the least effort possible.
It also tells you that the buffalo herd is doing very well and this is just culling for numbers control.
Why should the park take care of it? The calf became a hazard by following people. The hazard is that the calf wasn’t rejected. If the cow came back and found it among people, she’d probably kill a few.