What’s ironic about your comment?
Irony the expression of one’s meaning by using language that normally signifies the opposite, typically for humorous or emphatic effect
Are you saying it ISNT obvious that Jimmy Carter is out of the running?
The irony is that, opposed to my suggestion that Jimmy Carter would be a good choice, he is an obviously poor choice for a candidate because he’s in hospice. Ideally, the effect would be to likewise draw out the point that, apart from age alone, the problem with Biden is his overall condition and ability to campaign effectively.