It's a bad idea, but orders of magnitude less of a bad idea than drunk driving. People ditching cars means less drunk driving (even if it means more drunk cycling), as well as less road deaths in general. That can only be a good thing.
If you kill yourself while cycling then you were almost certainly hit by a car, which is probably more likely if you are drunk cycling. But this is also the fault of bad cycling infrastructure and arguably the driver who cannot avoid another road user.
Also, you might kill yourself by drunk cycling. And that is likely to have a huge effect on lots of people you care about.
It's just a bad idea all round...