I am not opposed to the pistols...
But he has a point on many of the newer designs, and the M&P being... In effect... SA triggers.
They do have more takeup and total trigger travel than traditional SA pistols using a hammer, but are mechanically similar in function internally.
On the Glock, the slide cocks the striker only partially, maybe 50% give or take. Then the trigger physically moves the striker back the rest of the distance before release. I tend to call this a partially cocked DA.
On pistols like the M&P, HK, and others the striker is held by a sear, that rotates out of the way, the striker sits at its full rearward travel point when at rest in the normal shooting configuration. The PPQ uses a weird falling sear like arrangement, but is in effect the same as the rotating sears.
Any rearward travel that the strikers have in these pistols, is minor, and more akin to positive sear engagement than DA, or even partial DA.
Now they all have drop safeties, and longer trigger pulls to help increase safety... So I have no problems with them myself... My carry guns are M&Ps of various models.
Its just that from a pure mechanical standpoint, of how the striker is released... They are in effect SA. The new Canik even puts it on the side of the slide... "SA"
So yeah... There is not a really good cut and dry "this much movement is required for DA" definition... I look at it like this.
If the trigger can draw the hammer (or striker) to the rear and fire the pistol, when said hammer (or striker) is in a fully relaxed state... Then it is a DA. (Example being a S&W SD series, or the Walther P99 which is DA/SA)
If the trigger will not draw the mechanism back from a full rest position, and relies on slide movement to reset the mechanism to a firing state, but the mechanism is not sitting at a position, that should it be released from that point, can reliably ignite a primer... Then it is a partial cock/tension mechanism. (examples being a Glock and the FNS)
If the action requires the slide motion to ready the pistol to fire, and the final position is one that could reliably ignite a primer, should it fall from that point, then it is a SA trigger... A rotating or dropping sear is pretty much a give away of this type. (Examples being an M&P or Springfield XD)
Even if some minor camming is present, that being less than a few percent of the total travel distance. (example, the noticeable hammer camming of a CZ75 in SA mode)