You’re right. The right of passage for most US computer science PhD programs is publications in the “right” journals and conferences. If you don’t publish you will rarely get past your thesis proposal. I think there are very few, very select professors in the US that prohibit publishing prior to graduating. But their count is likely in the single digits.

Also, by some miracle you manage to graduate by minimal publishing or no publications you will find all doors to getting research funding shut. This means that you are basically unemployable as a tenure track professor (universities prefer their newly minted assistant professors to come with funding).