Well there’s truth in it in that they quoted the Church Fathers and the Pope showing that Mary has always been venerated with the highest possible praise which can be given to a creature. But it’s a pretty typical Protestant manner of argument, assuming that all this means we somehow worship Mary and put her in the place of Jesus Christ.
From one of those quotes, from Pope Pius XI:
“Has not Jesus placed in your hands all the treasures of His grace and mercy?”
I’m no philosopher, but I think the author of this article could benefit from some basic philosophy. If Jesus who is God put in Mary’s hand all the treasures of grace and mercy (hence Mediatrix of All Graces), then it is self-evident the grace and mercy did not originate in her (that is, she is not the Creator) and therefore Jesus is infinitely greater than her, while she is vastly greater than every creature.
As I see it, Mary is so glorious, we with our finite minds would not be able to discern the difference between her glory and God’s infinite glory if we somehow saw it, though thanks to revelation through the Church we know God’s glory is actually infinite and hers finite. Maybe these people just need a true Church or something, I don’t know. But understanding what the Catholics actually believes and means when she speaks about Mary is not necessarily interesting to them.