No, Additive, Subractive, FM and VA are all methods of synthesis. Any synth whose main envelope parameters are attack, sustain, decay and release are in the ADSR category.
And why not, they should fuck around with multiple synths and notice the differences between them and see which ones they like. Then they can dive into that particular synth. I personally don't like doing the same thing all the time and like to keep things fresh so I fuck with multiple synths. If I stick with the same synth all the time I get bored.