Thats is beacuse we have yet to see if there is any long term in crypto. Even Bitcoin cannot be called a long-term success yet. 95% of altcoins die within months, some stay around for longer but fail to attract any new investors. Basically every single altcoin has been a pump+dump more or less, except for those that die right away and skipped the pump part.

That is the reality. The "long-term" investors are usually becoming bagholders. Now, this coin might be the exception (or not), but you cannot really critizise people for selling early, most of the time they have been proven right.