It’s clearly not important, but it’s Friday…my point on climbing and sprinting refers to this:
The rider shall normally assume a sitting position on the bicycle
In theory the UCI could do riders for taking a hand off the bars to feed, but, again we assume that is a sanctioned ‘abnormal’ position.
Ruleset is here BTW: https://www.uci.org/docs/default-source/rules-and-regulations/part-ii-road/2-roa-regulations-e.pdf
A lot of the familiar riding positions in the sport are only implicitly sanctioned, rather than explicitly. AFAICT