OK, I see now. "Follow for" isn't actually a phrase here. The writer is saying that you can "follow" a particular website (or blog, or whatever it is), and if you do follow the website, what you will get is "brutal honesty" (or "updates," in the second example). In the sentences you quoted, the word "for" means "in order to get." You could say, "Listen to your father for good advice." This means you should listen to your father in order to get good advice. You could also say "Read a newspaper for the latest news." This means that in order to get the latest news, you should read a newspaper. In more formal and correct speech, it would be better to say "Follow this blog for brutal honesty" or "Follow this website for updates," or something similar. However, it's common in online writing to simply say "follow" when what you mean is "follow this page that you're looking at right now." Both of the authors here are telling you what to expect if you choose to "follow" their pages. In these cases, you can't take out the word "for." For example, simply saying "follow brutal honesty" doesn't make sense. The author is telling you to follow the website. "Brutal honesty" is simply what you can expect to get, in return for following the site.

I think you may need to explain the context. By itself, the phrase "follow for" doesn't make any sense.