First of all, the stats don't say that many of them are using mobile almost exclusively. As I previously said, the way it is written leads me to believe that "mostly" to them is "more than 50%". Almost exclusively implies a much higher percentage of use.
And in any case, if people are only going to spend 5% on news in general while on mobile, then I would most definitely not optimize my site for them unless it were incredibly simple to do so. The 5% is then further split across many venues, and, as the source says, it includes in-app usage. That even further fractions the amount of time spent. With that much fractioning of the time, the chance that a user will even see this piece is pretty low.
Huh - so 5% of mobile browsing time dedicated to news sites isn't worth optimizing for - but the 4% of desktop web browsing time that is dedicated to news sites (same link) leads you to believe you should optimize (only) the desktop web experience?
I guess I just don't follow your logic.
Ignore mobile if you like. But good luck with that. Mobile users will find an experience that is optimized for them.
Except that, most of the time, there is no optimizing for the desktop. With most web developers still creating desktop-first experiences, you only have to consider whether or not it's worth it to create a mobile experience.
And in any case, if people are only going to spend 5% on news in general while on mobile, then I would most definitely not optimize my site for them unless it were incredibly simple to do so. The 5% is then further split across many venues, and, as the source says, it includes in-app usage. That even further fractions the amount of time spent. With that much fractioning of the time, the chance that a user will even see this piece is pretty low.