This could be the story of literally any large tech company today. Airbnb got its start by spamming people offering vacation homes for rent on Craigslist [1]. According to The Facebook Effect [2], Facebook was almost entirely dependent on its contact importer/spammer for its growth in its early days. On days when Hotmail blocked them for spamming, new user sign ups dropped by 80%; it was only after they cut a deal with Microsoft that included an agreement to not spam-box their emails that they continued to grow.
When you look behind the curtain of successful modern startups, virtually all of them were built on mountains of spam and bad/unethical/illegal behavior, which they then publicly decry and block on their own platforms after they become influential enough to do so. If you have issues with this, Silicon Valley probably isn't the place for you. There are plenty of tech jobs in other areas - but look away from startups, because most are employing/willing to employ extremely aggressive techniques to win.
[1] http://davegooden.com/2011/05/how-airbnb-became-a-billion-do...