A New York commercial services office didn’t break the law when it fired a software developer who complained about being misclassified as an independent contractor and thus missing out on health insurance and other employee benefits.

That’s the conclusion of the National Labor Relations Board’s Division of Advice in a memorandum released May 15.

The National Labor Relations Act protects employees who join together in “concerted” activity for their mutual aid or protection.

Here, the software developer acted alone and...