I beg to differ.
I've bought more than 10 BTC as a non-sg based person.

Ive got about ~700 accounts.
Of which
200 are probably non-sg based people just registering to have a look and will never buy or sell a single satoshi.
150 are probably russian/ hackers trying to look for a vulnerability
350 is my best guess of people based in Singapore who have registered.
Of these id say only 30%(~100+) have ever had any transactions at all, the rest are just looking atm.
Sometimes i wonder why am i even doing this