My views differ, anyone can argue they interpret 'commercial purposes' differently but it is very very hard to argue out of accepted industry norms. Know that these clauses were probably written by a team of corporate lawyers, probably the best in the country, given the organizers' financial might and the viable profits (or loss) involved. Thus I would be wise not to even try interpreting it different.
Simply put, commercial purposes is using the purpose of commerce, which means sales, trade, barter. If you read the TnC, it explicitly states "for profit, commercial gain, public advertisement, display or for any other purpose except for the private enjoyment of the person making / recording the Footage,"
They pursue legally, you are liable. Plain and simple. First for the breach of contract (ticketing part), second is possible sue for damages.
The situation might be different if you are hired in advance by some big shot or important personality to take personal pictures of him at the event, like a personal photographer, whereby this case you aren't selling photographs but merely selling a service. In this case you become sometime like a 'semi-official photographer' but maybe with limited access. The photographs would either belong to the hirer, or to SGPPL depending upon prior agreement between SGPPL and the person who hire you. You usually have no say in this. But as mentioned, it should be hired in advance, not selling of photos after you taken them in the capacity of an ordinary ticket holder.
As an ordinary ticket holder taking photos, your photos can only be used for personal enjoyment. Hope this helps.