Well, in this specific instance (using the bonus action shove from Shield Master before the attack action) - the Sage had made one ruling that (almost) everyone agreed with, and now he has reversed that ruling. And a lot of people don't agree with his logic for the reversal and are pointing out flaws in that logic, or discrepancies they believe are created as a result.
So we don't really want "the rule", because we already had that (or so we believed). And now the Sage is changing "the rule" (i.e. the clarification he'd made earlier and that we have been using) and is now claiming that the new ruling is the way it was supposed to work all along.
For some of us at least, we don't agree with his new position and don't intend to change our games. It's been the de facto ruling for too long, and worked just fine. We don't care for the disruption caused by trying to change something we didn't have a problem with.
Fortunately for me, none of my AL characters have the Shield Master feat so this doesn't affect them.
Their credo is build your own game.
considering that, It is perfectly normal that they give opposite advices in sage advice.
You say you don’t want « the rule » but you are also angry that he give an advice against your ruling.
Your ruling is fine, his advice is fine too. That is my point.