Keep in mind, the time period that at least the first few books of the "How Few Remain" series takes place in a time when racism was alive and well, and the norm for the majority of the world.
The writer shows various characters as smart, capable and clever, regardless of their color or ethnicitiy. This tends to counter the cry of racism, in my opinion.
That being said, while I enjoy his writing, it tends to be a bit repetitive. And his usage of stock phrasing gets be a tad heavy handed... yes, we know he's a fair skinned redhead, yes we know he's gonna put zinc on his nose, yes, we get that he would prefer to be in a cooler cloudier clime... is it necessary to mention it every time the character is active?
Stirling has the same issue, imo. He has a handful of stock characters (the wise and bad ass foreigner, the tough kick ass