Actually I suspect that the original post is right about the 1hbh tending to have more topspin than the 2hbh and I'm sure Gasquet hits his bh with massive topsin.
But the idea that the 1hbh is good because it allows you to "hit heavy topspin on head-height balls" sounds a bit off to me. How often are most players going be hitting a head-height ball with a topspin 1hbh? And is heavy topspin a realistic priority for a shot like that? It doesn't really make sense.
Tennis_hack and his earlier incarnations have a collective obsession with topspin and the 1hbh that borders on monomania... here's an example from one of his past lives
, and here is another