Heinlein was a product of his time . . .

. . . and also not one to "throw bones" to anyone. The very idea that he would write something to appease the establishment flies in the face of his entire career. I think he knew that sex with prepubescent children was problematic on more levels than just public disapproval. He as also staunchly anti-crime and depicted worlds where all criminals were killed, regardless of their offense ('Time Enough for Love' had one as I recall.) Although his political views fluctuated wildly throughout his life, he was a libertarian at heart, and the libertarians I have met are amongst the worst antis I've ever encountered.

As I said, you have to factor in several things: Heinlein was a product of the seventies and very much disliked the hippie movement and all it stood for; much of the time his writing seems calculated to piss off the counterculture as well as the establishment. The 70s perspective on sexual contact with kids was a lot different than it is now, and were Heinlein alive today I am reasonably certain he would have a markedly different view on the issue--he would view it as criminal behavior of the worst sort. Thirdly, the idea that Heinlein recognized that children had a sexuality and could be attractive does not suggest he would've been in favor of sexual contact with children. Finally, let's remember that this is fiction--you can only go so far in drawing conclusions about what Heinlein personally believed from his fictional writing, which you have to admit was socially and politically all over the board. I think the one thing we can really say about Heinlein is that he wanted to stimulate debate about these issues and wasn't afraid to challenge established views.