Cypress has shipped over 1,700,000,000 of these chips since introduction. Asking for PSoC Designer/Creator in another OS will probably be met with a very large shrug.
And although the vast majority of these devices will be going to big industrial users, if I was Cypress I'd consider the cost of developing Linux/Mac versions against the prospect of losing a generation of tinkerers to Atmel.
Build automation for embedded systems is such a PITA. My previous job we had a build step that used AutoHotKey to click through the manufacturers 'proprietary tools'. You can imagine how reliable that was