I beg to differ. Previously, you could check-in online 24 hours before your flight, and select your seats. All of the seats were available at that point, and everyone on that flight could choose from the same set of seats. It was a level playing field.
Now, you can choose not to pay, and still select your seats 24 hours in advance. But you are left with whatever seats are left over, once everyone else who has paid has selected their seats. Plus all of those who are eligible for whatever reason to do so for free. So, the chances are that larger groups of say four or more would have to split up.
My point is that previously, you could choose your seat and ensure you sit together at the same time as everyone else - included in the price of your ticket. Now, you are pushed to the back of the queue and have to pay extra if you want to choose your seats and have a good chance of getting what you wanted.
Time will tell what effect this new policy will have. Maybe very few people would choose to pay for reserved seating, and it won't have much effect on those using the free selection at 24 hours. Maybe lots of people will. Plus, on certain routes, there will be many young families etc. who are eligible for free seat selection. But either way, they are playing on the fears of people who want to sit together, and the needs of people who (for whatever reason) need to sit together.