As for the irony, I could not agree more.
But then, I've never been one to beat around the bush when it comes to parting ways with an employee who's clearly not working out on the team.
For small startups, firings have an effect on the entire company. Absolutely make the right choice and let someone go if you have to, but it still has an amplified cost across the team.
I personally take responsibility for the emotional cost on the candidate. Asking someone to invest themselves in your company and then letting them go is a rough experience for the employee. It is the manager's responsibility to not churn and burn through people.
Missing out on a good one sucks, but in the best relationships both sides will wait for the right timing if necessary, in my experience.