From my own experience, I recommend the intermediate step of hiding newsfeeds before actual deletion. Especially if this is someone who see, even occasionally, in real life.
As far as "deleting" people in real life for not having the same parenting methods, well...I see your children are young. It's easy to the be the perfect parent initially. It gets harder later. Again, from my own experience, I found that as my child aged and I faced some really difficult challenges, I gave other parents a lot more leeway. I realized that I didn't know their whole story, just as they didn't know mine. We all have non-stellar moments, when our children and our days and our work and our spouses and our families have just pushed us over the edge, and we snap at our kids. And we all have our own family dynamics, and things that work for us, but not for everyone. Really, who am I to judge? I can remember, though, being pretty dogmatic initially...before life took me down a peg or two, lol!
ETA: Obviously, I mean behaviours *within reason.* I don't want anyone to think that I am suggesting that if you see someone regularly beating their child, you should just chalk it up to different strokes. I mean things that aren't abusive. Like the decision to formula feed, the decision to put the kid in daycare and work, those sorts of things -- things that one person may feel strongly about but for another, it just doesn't suit them or their lives.