I left Fastmail over the recent Oz decision with encryption. I was a paying customer since 2002. It pained me horribly to leave, but I had no choice over principle.
Other than diplomatic norms, once a person leaves a country, he is bound by the laws of the receiving country. I base this on common knowledge and also having lived in 5 countries myself.
Australia and New Zealand are rapidly becoming draconian. I have friends in both countries. They are thinking of leaving because of all of this. The entire knee-jerk reaction to guns in NZ is but the latest in a long line of stupidities the Kiwi and Aussie governments have been up to. For example, in NSW, if you have a knife painted green, you can go to jail because it's a "zombie knife". Think I'm joking? Look it up. The last "free" state in Oz is QLD. The rest of them are up to their necks in draconian stupidity.
If Australians are legally obliged to implement back-doors on behalf of the Australian government and not mention it to their employer, why would any of these tech companies want you?
You'd be a massive security liability to them.