I love this strip! I saw it when I was a little kid in an early Peanuts compilation and it's stuck in the back of my mind ever since. The "For the Kiddies" in funky script at the top drives the joke home.
Check out all the names: Mangle, Slaughter, Throttle, Jab, Terror, Choke, Crush, Run (something), Mob, War (twice), Thrill, Smash, Murder Comix, Killer, Hate, Ouch!, Hit!, Mur-something (maybe Murder again), Terror, Gouge, Stab!, Kick Komics, something I can't make out, Kill Komics, Murder Comics, Smash, and Blast Comics.
In addition to some rarely-seen cultural commentary from Charles Schulz in the form of those titles, we get Charlie Brown professing to being discouraged here. And the Druggist is basically an unseen character here.
Drug stores used to be an important center for the community. How far they've fallen since those days. I have never seen an operational soda fountain in a drug store in my life.
EDIT: Fixed comic.