One of my teachers gave us some プリント about the uses of ばかり, which is based apparently on the 新完全マスターN3文法 book. I have read her examples and the book's but I can't figure out if there is any difference between てばかりいる and ばかりだ. The book says they mean "always do ~ only, do nothing but ~, there is nothing but ~. Often used to express disapproval" and "repeatedly or continuously ~,without doing other things. Usually used in a critical way" respectively, which clears up basically nothing for me.
I found this question: plain form + bakari vs. te form + bakari, but they don't really explain the meaning of 辞書形 + ばかり with verbs like the one used in the question (泣く). I understand the nuance when verbs of change are used or it means "the only thing left is...", but not in other cases.
I also read this page: https://maggiesensei.com/2013/07/02/%E3%81%B0%E3%81%8B%E3%82%8A-bakari/ and got the impression that maybe ばかりだ is used for when something is happening repeatedly at a certain moment, but not necessarily always, and てばかりいる is for habits or actions that happen often, but I'm not certain at all.