It could be argued that finding a new home for them is worse in the long run as it has more potential to prolong abuse and captivity of whales. If the new home loosens their standards and started abusing the whales, new whales could be brought in and abused as the older ones pass away. Euthanasing could bring an end to that cycle, although none of options here are particularly good.

Someonen else linked a link where they can be rehabited, probably too much cost for the shitty park

Everyone is screaming about the treatment (and I mean justifiable), but no one is willing to offer an actual solution. I ain't an expert on the topic of Beluga whales, but I mean if a wild release was possible and the best solution, why aren't these people getting involved then? Likely because it's maybe not the best solution.

So that leaves the government of Ontario to step in, and OK, but problem remains the same. All these supposed sanctuaries that people want them to live in, again, where are they and why aren't they stepping in? Because such a thing might not exist.

Would love to be totally wrong here, but this has the makings of a boondoggle.

What would take longer to kill them, starving or the allegedly guaranteed death from releasing them?

Seems to me that they'd stand a better chance in the wild compared to being left in a tank to starve.