Ban Mandarin in the Office! No Chinatown Allowed!

Yesterday, something that probably barely happens in other companies happened in mine.

A non-Chinese colleague suddenly sent me his (BCC-ed) email to the Group MD pertaining the Mandarin usage in our company. He demanded a firm action from the management to enforce English as the main language in our company. Then he made a petition and asked everybody who was not Chinese Singaporean to sign the petition to ban the use of Mandarin in the office.
Basically, he was so upset and fed up with all our Chinese-speaking colleagues who always talk in Mandarin in front of foreigners and locals who are not Chinese and do not speak Mandarin. He deems this action is very rude and makes the atmosphere of the office almost like in Chinatown.
Is this reporting thing too much?

Personally, I do feel that people who keep talking in other language in front of the others who don't speak that particular language are annoying and rude as they make us feel left alone and ignored. Moreover, this practice is very unprofessional to be done in a formal business setting. But yes, I would say yes, my colleague's action in reacting to this issue was just too much as he also made us (the foreigners and non-Chinese colleagues) to sign the petition he created. I think we can use a more 'subtle' way in reacting to this situation, for instance just by reminding them that it is rude to always speak Mandarin in front of those who do not.

The controversy is that we live in Singapore where Mandarin is widely accepted plus legally acknowledged and work with (mostly) Chinese colleagues whose mother tongue is English but they have been warned about their rude practice yet still practicing it. So, what to do?

Hokkian people would say: "Boh Wat La..."