Epithet posted the reply that I would have, so I'll ask you:- do you flat-out obey Sage Advice?
Because if you do then you have both obeyed his advice that you can shield bash before your first attack AND obeyed the advice that you cannot! But only one of these opposing interpretations is actually true, so we know that Sage Advice can be false. Slavishly, uncritically obeying is not the way forward.
On the other hand, if you do critically scrutinise the advice, how can you criticise me for doing the same?
I'm not talking about Twitter, I'm talking about the Sage Advice Compendium:
https://media.wizards.com/2019/dnd/downloads/SA-Compendium.pdf
Up until the most recent version, the Compendium has never said anything about Shield Master. The most recent version added a new section on the Shield Master feat, to specifically clearly up the confusion about the timing of the bonus action it grants. According to the Compendium, Jeremy's tweets no longer count as official rulings, though they may be a preview for future official rulings in the Compendium.
As I've explained, once I saw the 2015 tweet I played the feat as allowing the bonus action at any time (i.e. before the Attack action). In 2018, when he corrected that ruling, I stopped doing that, because his explanation made more sense than his 2015 tweet. Once it was added to the Sage Advice Compendium as an official ruling of how it's supposed to be played, there's no more room for questioning how the words are supposed to be interpreted -- the Compendium contains an official ruling that the bonus action shove must come after the Attack action. At that point, I can decide I don't like the rule and change it for my table, but continuing to argue what the rule actually means seems kind of silly at this point. After all, isn't that the whole point of an official ruling about a particular rules question?
So, yes, I do take the tweets with a grain of salt, but I'm not talking about tweets here. I'm specifically asking about the Sage Advice Compendium (you know, the thing that started this thread). There might be cases where I decide to play a particular rule differently at my table, but that's a conscious choice on my part and not me trying to extract a different meaning from the words in a given rule while ignoring what the Compendium says on the matter. Tweaking the rules for my table is part of the job of being a DM, but that's very different to taking the position that because the Shield Master feat doesn't contain the word "then" after the comma that there is no trigger and thus you can take the bonus action whenever you like, despite the Sage Advice Compendium very clearly saying that this is not what the feat allows.