Well, I can assure you that I am not someone who has told others to kick rocks over being affected by the monorail being down. Just because people did, doesn't mean it's okay. Everyone has different concerns and it's crappy of anyone to say that their concerns shouldn't matter.
I saw this after we booked our trip in 2017. CBR announced the construction and closing of the food court. A bunch of people on here insisted it was no big deal, that we need to just deal with it and it won't affect anyone since the construction won't start until after 9 and they'll have food trucks. Well to us, it was a big deal since we sleep late, have kids who would have been woken up early and been crabby, and were dealing with food allergies and special diets that the food trucks wouldn't have accommodated. To some people, the construction may not have been a big deal, to others, like us, it was.
The point is, it's not right for anyone to minimize the concerns of others. The DSA's don't personally affect me in the sense that I've never smoked inside the parks, but it would affect travelling companions which in turn affects me, and I can see how it is a big deal to some.
As to your comment about smokers not having to pay anything due to this change, it's really not any different than your monorail situation. People picked a resort specifically to use the monorail. Then they had to use other transportation. They aren't paying more than they were before. People may pick Disney knowing they can smoke inside the parks. Now they have to go outside. No, it doesn't cost them more to do so, just like it doesn't cost people more to use the buses or boats to get back to their resort. It's inconvenient in both situations and takes extra time. In the case of smokers, it can take more time out of enjoying the parks, which would then decrease the value of the ticket they paid for. Similarly, if someone is taking into account the value of using the monorail into their resort cost, not being able to use it decreases the value of what they are paying for the resort. It's really a similar situation. Just as people were upset about the monorail and any number of other last minute changes, it's natural for people to be upset over the last minute announcement of the smoking ban in the parks. No matter what the change, it doesn't make it right for people to try to say they shouldn't feel upset or that they're not impacted by the last minute notice.