I doubt if there are investor that buy Bitcoin aggressively when the price is high rather what they do is accumulate using the DCA method because the DCA method help one to invest regardless and then whenever there is Dip then they will take advantage and double or buy aggressively. Buying when the price is high doesn't look or seen strategic and no matter the capacity of that investor buying aggressively when the price is high look unprofessional because the fraction of Bitcoin one will buy when the price is high and the one when the price will go down will not be same.
don't doubt because real investors who are investing in bitcoin for long term 5 to 10 years or longer buy aggressively at any price level, only those investors who there focus is on short term are the people who don't buy aggressively when is high, so don't be confuse to confuse others especially newbies, because you can buy aggressively at any price level if your focus is on long term holding.
We don't have anything to doubt or questioned someone if they are buying when Bitcoin bullish trends occur. We could actually see the sentiments since that give us an idea about what's really happening right now.
Also lots of discussion about that they are continuously buying that's why there's no reason for us to doubt about that situation since long term holders actually don't care about the prices but rather their main intention is to buy Bitcoin at whatever price it is since the main intention is to accumulate as many Bitcoin as they can while they have money to spend for this coin. What I doubt that they worry to much about those dips since for sure this is the less concern of long term investors. I encourage people not to have doubts on Bitcoin and buy then HODL since this is best decision to do with this coin.