There's no degeneracy here. It's a perfectly defensible line of moral reasoning.
The constraint is, there simply is not enough capacity to treat everyone. If there was, there would be no problem. So should you prioritize care for people who are intentionally making themselves ill, or those who aren't?
You have to choose one, after all. Are you advocating that people with illnesses other than covid should get delayed or denied care? Is that not just as degenerate?
This is a well-explored situation in other cases of shortages. Suppose that there is a severe famine and the government imposes food rationing. The Smiths abide by the rations and eat small but barely sufficient meals for a month. The Joneses refuse (for whatever reason), buy lavish amounts of ingredients, and throw out leftovers. At the end of the month the Joneses have blown through their ration cards and say they will starve the next month unless the Smiths share some of their rations.
The morally defensible answer is no, despite the danger that the Joneses may die, because if you say yes, now both the Joneses and the Smiths will be malnourished, this is an unacceptable harm to the Smiths, and being willing to answer yes will just encourage other people to act like the Joneses.
It's a trolley problem. You always want to just stop the trolley of you can or get people off the tracks. But if you can't, you have to make a choice about who it hits. Being in the position of making that choice doesn't inherently make you a murderer.