There's some plausibility in this. The importance of diurnal variation in testosterone may be underrated. It's known to attenuate with age, which at least correlates with a reduction in libido. Of course, as you note, introducing much larger and longer swings in testosterone can cause various other problems—with estradiol, hematocrit, etc. This is why I favor daily use of a propionate blend....
He says about 50% of the time when men change from weekly to more frequent injections they lose their libido. ...