contact was not "enough".
The problem with this thinking is that the foul really isn't a blocking foul (i.e. BBW, IBB, holding, etc.) but rather an interference foul like D/OPI, KCI, etc. Yes, we CALL it illegal block, but what are we going to call it? Blocking is what they're doing where in the other cases, the players are by rule protected from CERTAIN kinds of contact or non-contact (KCI). The intent of the rule is so Team A doesn't put up a wall so that Team B doesn't have a shot at the ball.
I'm not saying ANY contact creates the foul, but any block that results in contact pretty much does. Maybe not 100% but close.