Because people have claimed for decades that breakfast is the most important meal and that you have to eat breakfast and made all sorts of unfounded claims with no evidence.
I have no trouble believing that breakfast is relevant to circadian rhythms. This is far different from saying that skipping breakfast inevitably results in "sleeping later and waking up later as the rhythm shifts towards your first meal of the day." This is a very strong claim that demands strong evidence. Some studies linking circadian rhythm to meals is not sufficient.
Firstly, you weren't asked the question. Secondly, you don't answer it. Proof was asked for yet you confidently come in with "Of course not" and no evidence or proof, for or against.
This is a public discussion forum. You can criticize my response. You cannot criticize me for responding. I certainly didn't ask for you to respond to me, and yet you did, which is perfectly appropriate.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4078443/
http://yaledailynews.com/blog/2013/03/05/eating-times-affect...
Here's a HN discussion regarding a Harvard study on the subject, from 7 years ago: https://news.ycombinator.com/item?id=199394
Please provide some evidence that these studies are insignificant and incorrect.