Any use of stigma/taboos/covert punishments seems antagonistic to free and open discussion which is important for our mutual enlightenment.
There are right and wrong times to say thing but the price a person should pay for being unkind is social ostracisation, rather than threats of loosing their job etc. People should be free to share their opinion but expected to back it up. There may of course be complications/limitations when a person is acting as a representative for another entity (E.G. A company).
Free speech should only generally be limited in instances such as blackmail, intimidation, incitement to violence or harassment/bullying and not in instances where a person's views about a group of people may be deemed offensive.