[turretslug]

I was a little puzzled by that statement, too, my assumption was that it was a roundabout (that's less rude than "evasive"....) way of saying, "because of the high residual capacitance of the Colpitts, it's less easy to get close tracking over a wide frequency ratio". Perhaps.

Presumably the author was thinking of a receiver with oscillator tuning control driving the calibrated frequency scale, and a mechanically separate RF preselecter control? It does seem lumpen though, with the near-certainty of hitting the image instead!