There's two sides to every coin. Price is a function of supply and demand. A tightly held stock might reduce demand as it's less attractive as a takeover target, but it also reduces available supply. I'm not sure it's on balance positive or negative, but I'm certain it's not a flat out negative as Strachan suggests.
There are two sides to every coin - the breadth of his work is superb, but the quality isn't always fantastic.