I think the most telling thing is that there is never any evidence given for these claims, especially given that there is a ton of data available. Which is pretty suggestive that the data doesn't support this, because if it did then we would see it.
Equally, shouldn't it be very easy to use the data to show that it isn't happening? If you can plot a line, it will either go down or not. But nobody has plotted the line!
