Because HH outdamage and outranges some of the CL/CA guns from higher levels. It was taken out of Blitz for that reason and it seems it carried on to CL/CA rooms.

Smart move if you ask me. 

GOOD!

Same crap for CV select rooms.
But the XP in those "boosted" rooms is still lower than in GBs - so who cares.

bb-ca room also.........this is  1 big joke:))))

This is a good thing

HH should never be effective against ships