If we agree that Sinhalese, Tamils, Muslims and other races as all Sri Lankans, just one nationality group, then there should be only only one representative for all of us. Therefore, only one national anthem, one national flag.
Singing the National anthem in Tamil will only highlight the differences among us-soon the Muslim brothers will want it sung in Arabic and the Burghers will want it in English, Chinese will want it in Chinese; if you say there are only a few Chinese people here, so that we don't need to sing it in Chinese, that will be 'discrimination' for a minority group; specially if we allow another minority group with a bigger population to have it their own way. (Majority among the minority)
What about those two stripes in the national flag, which are supposed to represent the Tamils and Muslims? It only indicates that they are not part of the big picture-the lion. We should remove those two stripes as well, because the lion is there to represent all of us.