I couldn't agree more with you. As a Sri lankan I know, for the most part, all cultures and religions of SL practice a great deal of tolerance and regard towards one another. Where I come from, Kolpitty Colombo, we have so many different races and religions living side by side, and we each mind our own beeswax and do our thing.
It's perfectly normal to hear the adhans, the Buddhist sermons, and Hindu chants all the time.
And we have many masjids all around the island, hence building one in a place where it will cause tension and violence is IMO wrong and provoking to say the least. My own cousins who lived in the same house as us, are Buddhists so I know quite a bit about the religion to know that the religion certainly doesn't promote violence and racism. Hence I know such situations as mentioned in the OP are started by vested interests who use such tension to further their cause.