If it's multiple kisses then it's suck'n face, but holding hand is absolutely fine. I hold hands with my friend who is a girl but not my girlfriend and I kiss her on her lips (one kiss for hi, one for bye).
Little kisses and holding hands is ok. But practically making out in public, is taking it to a whole other level that's not acceptable.. My hubby and i do hold hands and kiss in public. Little quick pecks, not long drawn out kisses. But anything else is saved for the privacy of our home. It's disrespectful to other people who don't want to see it. Plus i imagine if you're single and unhappy, it's a little like rubbing one's nose in it.
I like PDA especially with older people, it's lovely to see . I just hate people who go out off their way to show you how much they love each other lol
Others don't need to see how much you love each other . find a private place . not a public place . its a public place . its not for two lovers to show their love towards each other .
You can enjoy your romance at your own place . simple as that.