They shouldn't be, no. But many people will assume that you are not willing to hold hands because you don't like them. They will then think (incorrectly, of course) that you're mean or bigoted. We are not in Japan and you generally do not kneel or sing aloud in a grocery store either. So if you are in a church where the holding hands thing is custom, unless you have the disease, fear, etc., it may be kinder to just hold hands and then take it up with the pastor in private.
How about if the people holding hands understand that this is an innovation that should not be done in the liturgy? The instruction to hold hands can not be found in the GIRM. It can’t be found anywhere. Innovation has NO place in our liturgy. Why are we now the “Electric Church” as Mother Angelica put it? Every time you walk in, you get a shock.
To me, it isn’t a matter of kind. That person is intruding on another’s prayer time for a “feel good”. The kindness would come in waiting until the OTHER person held out a hand for you, rather than taking offense from those folded hands.
I don’t find it to be kind to give in. I find it to be a lesson to that person. Handholding is not encouraged in ANY diocese. None. Perhaps doing it right instead of kind would be a better idea.
And perhaps a good way to look at it is this.
Name one other place where you hold hands with strangers.
We kneel and pray in many places
We sing aloud in many more.
But we don’t hold hands with strangers and shouldn’t in Holy Mass.