Platinum is the only woman in the group, and her creation thus raises the most questions. When Dr. Magnus encoded her responses into the responsometer, did he base it on a woman he knew? Or did he base it on what he though women were like? Or even what he though women should be like? Platinum is unabashedly in love with Magnus, something that he repeatedly expresses annoyance at. And yet, as Platinum herself points out, he created her and could alter her personality if he wished. It wasn't enough then for Magnus to create a surrogate brotherhood, he must also have desired female companionship. This companionship allows him to receive female attention while continuously re-affirming both is manhood and his own disdain for female companionship by rejecting her. Imagine the ego boost of creating a beautiful woman to follow you around and profess her love for you, only to brush her off every time and watch her keep trying over and over again. In addition, the group is always called the Metal Men, even though Platinum was actually the first member. Either "Men" is meant in a broader sense, like mankind, or Platinum is not "really" a member of the group, just a hangers on or groupie.
Whatever his exact reasoning for doing so, Magnus has created an artificial family unit, all fiercely loyal to him, that he can repair and resurrect whenever they are damaged. Platinum serves as both daughter and lover, reminiscent of both Pygmalion and the Elektra complex. Is any of this intentional? Maybe not, although it's hard to say for certain. The standards of the time, much like the Hollywood Code, disallowed writing anything controversial or daring. Just like creative film-makers wrote around the Code, I have no doubt some comic writers wrote around the standards of the time. When homosexuality and transvestism was verboten, Jimmy Olsen was allowed to dress in drag and go undercover as a woman to solve a case. Lois briefly turned into a black woman long before any mainstream comic actually starred a black woman.
Even if the subtext behind the group was completely un-intended, some of their adventures certainly speak to male anxieties, either on the part of the author or to appeal to a young male audience. One of their adventures has the shy stuttering Tin whisked off to be the mate of the Queen of an Amazon like robot world where women rule and men are used as dogs. This could speak to young men afraid of relationships with women, in addition to young men who see their friends "taken" to a female/male social world while they are still stuck in the adolescent all male social circle. As the Metal Men go to rescue their comrade, the robot-men-dogs who are forced to hunt them rise up to throw off the shackles of their robot-Amazon rulers, allowing the Metal Men to rescue Tin and return to Earth.
Acknowledging and exploring all of these different elements from a perspective of critical thinking and feminism could lead to some fascinating stories. As far as I know, the Metal Men have yet to make an appearance in the New 52 re-boot, hopefully when they do show up next the author puts some extra thought into this unique team.