Plus most of the time it will be natural instinct to go for it. As for tapping it up to give you a better chance of catching it, then you would need to get close enough to get under the ball, probably not the biggest priority at the time.

Different treatment in league and union but rules in both broadly appropriate. As said, scrum advantage sufficient, and perhaps attacker should have thrown a better pass. That said, I think the current tendency in union to show yellow cards is way too draconian, but that's another story.

It's good defence, a split second reaction and it would be a bit harsh to concede a penalty by trying to prevent the opposition from scoring.

No different to deliberately slapping a ball out of play the in goal area to me, sacrificing possession to save a try!

I don't get this.
Just because Union have a strange rule for a deliberate knock on, it doesn't mean that we should follow suit.
In league there is very little reason to knock the ball on deliberately.
Ok if you are a single defender with 2 attackers coming at you, it's better to knock the ball on rather than concede a try.
However, the resulting scrum is sufficient advantage and there is no need to increase the "penalty" for such an infringement.

Also, there is nothing better to see than a player intercepting and going the length of the field and a change to the rules may just
reduce these moments and nobody should want that to happen.

Wasn't it Leeds who wanted the deliberate knock on rule introduced as their style of play was so predicatable, all the defences knew how to defeat them ?

in that case my bad. And he's spot on.