Context is king. We are talking about banning lumped PTO. Pretty much every company moving from lumped PTO to vacation+sick is going to make vacation smaller than the lumped PTO.
Most companies are going to use any change in leave policies to decrease total leave, if they're allowed to do so. This happened when pooled PTO became common as well - moving from, say, 10 days vacation and 10 days sick leave to 15 days PTO.
Not disputing that there are shitty companies out there, but I worked somewhere that did this exact thing (10+10 to 15) but it was explicitly said that sick days don't burn PTO. If you're sick you don't work, paid, and if it's more than 2 days in a row you need a note. Basically, treating the employees like adults.
If more companies did that people would be happier and more productive across the board.