a) I'm releasing a Mac app for casual DJs. Mac sites are probably underviewed by my demographic and I only have a few DJ sites I can directly target.

b) I don't have to promote to all 125 sites, I can be more targeted.

c) You're automatically treating growth hacking as spam. Growth Hacking is a common promotion process - the issue is how it is accomplished. Promoting on lists - good. Making fake websites with fake articles / reviews - not so good. Paying bots to upvote - bad.

Spamming is an integral part of growth hacking. As is the contact info acraping and harvesting. Pinning a cool name on these activities doesn't make them any more acceptable.