Just because M-W picks up on the vernacular doesn’t mean the rest of us have to follow them right off the cliff. “-gate” is one of the more annoying crutches of today’s drive-by media.
There’s no “cliff.” It’s a complete thought communicated with a single syllable. How would you replace it?
As long as reason trumps emotion, I’ll continue to embrace the use of “-gate” and dismiss “homicide bomber” as utterly stupid.