These days it is very hard to hoard Bitcoins. Truly, you would need millions in order to do so. However, it is good for Bitcoin because maybe there will only be 15,000,000 coins because many coins will be lost over time (there are supposed to be 21,000,000) but if you keep them the demand will rise and therefore the price will rise too.
You don't need millions to hoard bitcoins. You can hoard the few bitcoins that you have. Even the people scraping satoshis off faucets contribute to hoarding. In the end, it reduces the available supply and price increases.
Correct, holding is not an activity done only by whales, even if you only have a few BTC then and you have not moved them for a long time then you are hoarding them, to be honest I do not see any kind of problem with that tactic, because bitcoin does becomes more valuable the more you hold it.