This is really poor argument, and I can give an example why.
Among the Democratic candidates for 2020, Beto is on the centrist road. As Democrats go, he's a left leaning moderate. Bernie Sanders would be an example of a candidate on the left.
But back to Beto. According to this guy in your youtube video, Beto should be supporting all of the following for sake of "finding the middle ground)
- Expanding border walls
- Militarization of the southern border
- Tolerating fascism
- Supporting family separation
- etc
Except that Beto has been the most outspoken critic of these things. He just called out Trump for using rhetoric that is similar to what the third Reich used. He's been fighting against family separation strongly and successfully lobbied one of the government contractors to shut down their camp. He's advocated scaling back the amount of border fencing we have in place already where it makes sense to do so. Etc.
And as a left leaning moderate myself, I support him in all of those things. You see what I mean? This youtube guy leads with a false premise (that moderates are about finding common ground between the left and the right). That's not what it is. He is correct that the percentage of the electorate that identifies as moderate has been shrinking, but he's completely mis-characterizing what it means to be moderate.
It's a waste of airtime because it's addressing an audience that by and large does not exist. He's made up his own bogeyman.