Could we not compare learning with working (on both or more sides of this issue).
A working person works as much as he, and his wife, wants him to. In my opinion, most, including myself, should work less and spend more time learning and raising their families.
A modern learning person is usually supported by someone else. If he is supported by the working wife or a shver or a Zevulun, he should learn as much as they demand from him. If he is supported by the kehillah, then CR posters can question his time, as much as they are part of the kehillah … If they are, fully or in part, supported by US or Israeli taxpayers (directly or thru their wives and sponsors applying for various programs), then they should make sure they are not violating any laws and creating any Hillul Hashem by channeling funds for poor people into their learning. In this case, shteiging 24 hours a day will not help, same as cooking pork for 10 hours will not make into kosher beef.