“They” would be anyone he’d be talking to who wants to cause trouble for him.
Stockpiling is what you do as a good boy scout to be prepared for something that COULD happen. It is taking personal responsibility to not be a burden on your neighbors or community. It is self-sufficiency. Not greed.
Hoarding is what people do AFTER something happens where possible limits on how much you can buy are in place so that the unprepared people can have some time to buy items. Hoarding cuts into the greed some people might have to clean out a store AFTER the SHTF and not care about anyone else when they had plenty of time beforehand to prepare.
That’s why if there ever IS a SHTF moment, your prior preparations aren’t ‘hoarding’ and should not be explained as such, otherwise word will get around and authorities will be notified you are ‘hoarding’ when you weren’t and guess how fast that stuff will be taken from you unless you have your receipts.
Greed never enters into it if you to decide to put back that which you legally earned, no matter the words used to describe it. It is, as you said, self-sufficiency.
Also, I doubt that anyone who suspected someone was "hoarding" would be satisfied and forget the whole thing if they were told it was not "hoarding" but merely "stockpiling". Word games won't satisfy those who will want to make trouble for you. Best bet is, if the SHTF, to just keep your mouth shut if you are stockpiling or hoarding anything.