A few things. Bala goapala tarangam is in Sanskrit so your logic is already wrong. Secondly this is not Tamil Sangham to speak in Tamil. More important, you're assuming the speakers and every single listener is Tamil which clearly isn't the case because it's probably performed in the US so take this whole random rant of speaking in a particular language somewhere else.
You guys are all stupid because this is a Kuchipudi Rangapravesam and I guess you guys think Tamil is the superior language and don’t consider where Kuchipudi comes from and the language of Telugu.