If bigotry is defined as “intolerance towards those who hold different opinions from oneself” then, in my view, a person who labels another a bigot because of differing views, is, in being intolerant of that person’s differing views, being bigoted him/herself.
It’s thus a redundant and useless word, surely aiming only to intimidate and silence the voice of people who differ from you. This behaviour may have been typical in our distant past, but is unacceptable now.
The Bill of Rights in our Constitution allows, accepts and promotes a plethora of views, beliefs etc ( and of expression ), knowing full well that many of these will differ, even oppose each other.
Someone who labels another a bigot is acting contrary to our Constitution.