Seasonal bosses need Health up ?

It is extremely strange that no one said that the low hp of seasonal bosses is a disadvantage.
You like the 27,500 hp Dragon Fly, which got x10 hp compared to the DS.
But Deerclops and the other bosses only got x1.5-x4... It looks rather illogical... Moreover, many can also be avoided, and Moose does not even come to you. 
Yes, and from the point of view of logic... DST hp from bosses is not logical. Just like the Merms.