Hi and welcome!
Knitters make slip stitch edges in a variety of ways. Here are some different methods
I tend to slip knitwise and purl the last stitch but it's up to you whether you like this edge or not. For socks, the slipped sts make it easier to pick up sts for the gusset, The slipped sts won't show anyway.
I wonder if slipping 2 is a mistake in the pattern? I've only seen patterns with a single slip stitch here. I agree that the edge is not pretty with the 2 slipped sts. Why not just slip one at the beginning of each row?
I think that there is an assumption that you will use your preferred technique for the edges on this sock based on experience and personal preference. If this is one of your first socks, you'll be learning as you go.