There's no tradition in PA of requiring fish to be kept entirely in the water during release (at least none that I'm aware of). Because of this, when PA anglers hear that they have to release fish immediately, they just assume a pic is okay...and they don't note the literal letter of the law.
In FL, by contrast, it has long been publicly understood and accepted that tarpon and goliaths must be kept in the water. But these are big fish (apples to pumpkins, so to speak) and lifting them is often not possible anyway.
Here in PA, anglers just aren't habituated to such an ethic (whether we should be is debatable).
This is an unorthodox rule and was not well publicized by the PFBC when it went into effect. I think the PFBC may have a tough case to enforce such a citation, at least for a couple years. My personal view is that, if the PFBC seeks to continue to enforce this policy to the letter, the state's anglers should get a grace period and the PFBC needs to do a better job with getting the word out.