To be fair, the increase in the number of votes is simply a function of the fact that there were more votes cast - 21% more in fact. The SNP share of the overall vote (which is a slightly meaningless figure..but hey ho) didn't significantly change. They got 32.3% of the first preference votes in both 2012 and 2017.
The Tories more than doubled their first preference votes. (from 206,599 to 478,073) and increased their share of the vote from 13.3% to 25.3%. So they did make clear gains.
What certainly isn't true, is that people are 'turning away from the SNP'. The swing to the Conservatives was almost entirely from Labour and Independents/Other in terms of votes, share of the vote and seats.
Yes, you are of course absolutely right. (The complete set of figures wasn't available when I made that earlier post.) But when any party gets more people voting for them on that scale, you can't then come and say that voters are turning away from the party.
The SNP's share of the vote was level with its 2012 figure, so again no support for the "turning away from the party" assertion.
The Tories most certainly made clear gains - from Labour. As I've been saying in a number of earlier posts. The Tories pretended they were fighting the SNP when they were in fact competing with Labour for the hard-core unionist vote. That's why they campaigned on the single issue of "no second referendum". Of course Labour also campaigned on that issue almost exclusively. The leaflets were a bit surreal.
The Tories won that fight. They grabbed a huge pile of previously Labour voters and went from being a long way behind Labour to overtaking them (just). Meanwhile the SNP sailed on undamaged.
This is where the fake news comes in. The headlines go on and on about how well the Conservatives did. Sure they came from a poor third to just sneaking second place. Well done them. Then the headlines go on and on about how badly the SNP did. Except it didn't. The BBC even fiddled the figures quite shamelessly so they could report the SNP as losing council seats when they had in fact gained six.
Then in the minds of the public who are only half paying attention, this somehow comes out as the Tories having beaten the SNP, or at the very least taken votes off them.
The absolute cracker is what I posted in the post you quoted, when the leader of the party who were absolutely pasted by the Tories, who lost a hell of a lot of seats and votes, the party that used to run Scotland as a one party state and is now firmly the third party, runs to the press with a quote that "people are turning away from the SNP."
And instead of saying, go back to school and learn some basic arithmetic Kezia, the papers just print it as "news".
ETA: Nice illustration, perfectly sums up what happened.