Because the latest one in the day for him is 5:30 in the morning. That's a bullshit time. The time of day that Crowder originally agreed to was reasonable for both parties. At essentially the last minute, Crowder backs out and claims a schedule change. That's fucking bogus.
And Potholer isn't a "low rated Youtuber". He does his YouTube channel as a side project to career as a seasoned and highly respected science reporter.
In fact, immensely popular-among-science-geeks science-and-bullshit-debunker, Thunderf00t, considers potholer54 as one of the remaining science YouTubers he absolutely respects for his YouTube contributions to debunking anti-science bullshit, and Thunderf00t has a roughly comparable number of YouTube subscribers as Crowder.
Also, Crowder only wants to "debate" with Potholer if he does so as a guest on Crowder's show. That is not a neutral setting for a debate, and Crowder knows this. He's not interested in having a fair debate on the topic. He simply wants to media whore whatever exchange with Potholer that he could manage with the help of his show producer. That's bullshit.
P.S. And if Crowder think nobody cared, why did he take the time to respond to Potholer's video about his non-appearance on the debate?