@Julien ********
, you are confusing two completely different things.
BEFORE 2015 you could apply for double and even triple entry tourist visas at the various thai consulates.
BUT
On Friday 13 November 2015 they started offering tourist visas only two ways a single entry and a 6 month METV <-multi-entry tourist visa. That was also the time that most consulates (especially ALL of the consulates in S/E Asia) put a residency requirement on the 6 month METV meaning you had to legally reside in the country you were applying for the METV in.
The Thai consulates in Australia are the ONLY consulates nearby that do not have the residency requirement. Other than them you would need to go back to the country your passport comes from to get a 6 month METV.