JAJ, from the EEA/EU regulations that came into force on 30.04.06 (much of which is a repeat from earlier regulations) :-
7.—(1) Subject to paragraph (2), for the purposes of these Regulations the following persons
shall be treated as the family members of another person—
(a) his spouse or his civil partner;
(b) direct descendants of his, his spouse or his civil partner who are—
(i) under 21; or
(ii) dependants of his, his spouse or his civil partner;
(c) dependent direct relatives in his ascending line or that of his spouse or his civil partner;
(d) a person who is to be treated as the family member of that other person under paragraph (3).
(2) A person shall not be treated under paragraph (1)(b) or (c) as the family member of a student residing in the United Kingdom after the period of three months beginning on the date on which the student is admitted to the United Kingdom unless—
(a) in the case of paragraph (b), the person is the dependent child of the student or of his spouse or civil partner; or
(b) the student also falls within one of the other categories of qualified persons mentioned in regulation 6(1).
(3) Subject to paragraph (4), a person who is an extended family member and has been issued with an EEA family permit, a registration certificate or a residence card shall be treated as the family member of the relevant EEA national for as long as he continues to satisfy the conditions in
regulation 8(2), (3), (4) or (5) in relation to that EEA national and the permit, certificate or card has not ceased to be valid or been revoked.
(4) Where the relevant EEA national is a student, the extended family member shall only be treated as the family member of that national under paragraph (3) if either the EEA family permit was issued under regulation 12(2), the registration certificate was issued under regulation 16(5) or
the residence card was issued under regulation 17(4).
Accordingly the point you make is not valid, given that my wife's children are my family members under the terms of the EEA/EU regulations. That is, notice in 7(1)(b) the inclusion of the words "his spouse".