I'm a software engineer who does not practice "tech veganism." I use an iPhone, iMessage, Gmail, Google, Google Docs, etc. I'm interested in understanding why people who do practice this feel so strongly that using these products and services is bad. So what if Google reads your emails? Why is it bad if they correlate those and your search results to offer a more personalized service -- even more personalized advertisements -- for things you might actually be interested in buying some day? Is it fear of public embarrassment? Of being blackmailed? Of being discovered doing less than legal things? Have you been slighted by the company before so it's a matter of never doing business with them again out of principle?

No need to worry about explaining it kindly and plainly to me :)