Poly bigots

There are of course, polygamous relationships, where a man who keeps multiple wives living under the same roof will consider they are in a valid marriage with all of those wives.

Now, whilst I do not object to people forming whatever consensual relationships they choose, one guy keeping multiple women doesn't meet with my understanding of the word "marriage", and I'm not inclined to change the definition just to pander to their social engineering. Equally, I'm not inclined to say de facto relationships mean exactly the same thing as a marriage. and quite a few people in de facto relationships happen to prefer such a differentiation too, for that matter. My line of thinking can be seen merely from the fact we have different words to indicate different meanings. We differentiate between marriage and de facto, or marriage and polygamous marriage.

The burning question in today's society though, is am I permitted to consider such relationships as something other than marriage? Must the definition of marriage be changed to fit what polygamists insist is equal to marriage in every meaningful sense of the term, or are we permitted to have a different opinion? Are we permitted to hold fast to our understanding of the meanings of words, and argue to hold those meanings, without being branded a "poly bigot" for not playing along with harem builders?