Online scanner apps have little to do with agencies ENC. their radio traffic.
Yes, it does. No police dept likes it when other people listen to them, but they can deal with it knowing it was only a very small amount of people listening. Now it is freely available to anyone with a smartphone (which includes pretty much everyone under the age of ~30).
Think of it this way; If you knew that 5 people at any given time were listening to your phone calls, you wouldn't like it, but you could deal with it because it was only 5 people. Then one of those 5 people decides to rebroadcast your phone calls over the internet to be heard by 5,000 people. My guess is that now you would have a real problem with it. This is exactly what is happening with these feeds and apps.
seems to me there are endless and pointless threads started everyday about online scanner apps and not being good for the hobby.
Perhaps that is because it IS bad for the hobby; In more ways than one.
It is bad for the reason I just explained above, and it is bad for the scanner industry in general (which in turn, is bad for our hobby). For our hobby to keep up with the times, we need the scanner manufacturer's to keep developing new scanners to keep pace with technology. As long as we keep buying them, they keep making newer and better scanners. Well why would somebody buy a ~$500 scanner when they can listen on their phone for free? I personally know two people who have older (<100 channel, analog) scanners who refuse to buy a new one and use the phone apps exclusively. I know they are not the only ones. If the revenue stop coming in, then the production and development of new, more advanced scanner will stop with it.
Bottom Line; I can see how the free feeds/apps have a negative effect on the scanning industry and our hobby, but I can't think of a single way it helps either one.