Because if you're off 28, then playing well means hitting 99 or less. Breaking 100 is almost the goal for everyone when first getting into golf, no matter what age.
When you can win comps by hitting 120, it seems kind of ridiculous to be honest... Firstly you have the amount of time that it will take to complete the round with scores like that. Then you have the fact that when newer, younger players who are given high handicaps play, they are often improving at a rapid rate. If the original poster hits 100 like he did off a 28 handicap, he's hitting nett 72 or around that. Not nonsense like 55
Nothing against anyone with high handicaps by the way - they didn't make the changes, so best of luck to them!
There is no point in playing a handicap sport, where you're getting an advantage over some opponents, and then moaning that other people get a bigger advantage. The limit was 28, it's now 54. They are both completely arbitrary limits but one is more inclusive than the other. We all play to the same rules and the handicap system does its best to keep up.