Why WOULDN'T the Hellbringer have ECM?
no reason really.
but this will be the first heavy with ECM. for a long time the only ECM units were lights, mediums, and one atlas. the players created an explanation for this that boils down to "heavies with ECM are too overpowered', even though PGI never said that.
so a lot of people assumed that the hellbringer would not carry ECM because of that.
of course, the real reason is that in 3050, ECM carrying mechs in general are uncommon.. and ECM heavies are pretty rare.