Perfectly said.....
Its nothing different from the christians who also wear black on mourings....or the hindus who wear white.
I mean in our faith the color black itself represents sorrow, mouring or grief. And for the same reason u wuldnt find any1 wearing black to a wedding.
And for clearance, no1 wears black in Muharram becuz they believe it was Hazrat Ali's fav color nor do they do it to replica the Prophet (PBUH)'s way....