You really think everything "enforceable" in a society has to come via handcuffs and jail sentences?
Speaking openly about the dislike and morality of older adults going after 16-year-olds acts as a decent deterrent in a society to show we largely think, as a collective, it's not acceptable even if legal. Maybe you're hanging about some dodgy high schools, but for the rest of us we don't tend to see many adults who could pass as teenagers dads picking them up, in a relationship, from high school.
Society does not a bad job of socially setting "boundaries" we think are reasonable even if they aren't codified precisely in law. What doesn't help is posters in this topic telling everyone to be quiet and stop speaking because it's just "outrage" or see the below, "too close to my daughter is dating a black man".
You're really going to play the black man card in this topic in order to contrast that to your hypothetical 16 year old daughter dating a 35 year old?
Historically society has often done a terrifically bad job at setting boundaries and to be blunt unless it's enforceable it will be ignored in current society. Do you actually think that an older guy who wants to date younger women won't because some will frown on it? People who want to do that aren't going to give a damn. Check on Seinfeld, etc. They don't care.
Sure in the past people tended to avoid anything frowned upon that could harm them but today? Forget it. It's not the case in Western society. Unless it's illegal it's going to happen.
You're trying to apply social diapers and it doesn't work and it's never really worked. The evidence is against you.
For the record as noted I don't myself think that kind of age gap where the guy is older and the woman is a young teenager is advisable, not because of any social mores (I give a fuck about those as much as eating with the right fork) but because the chance of abuse and misuse of experience is high. But that's neither here nor there in terms of impact on anyone's behavior.
And TBH as per my original reply to the question in the OP: the reason there isn't some huge issue or backlash is because the majority actually don't view it that way or deem it worth concern without evidence of actual abuse.
Keep arguing if you wish but realize I'm merely noting the facts as they exist today. Beyond frowns this behavior doesn't get nor legally warrant further response and as with the current lack of interest or outrage that will continue to be the case. I'm done though. I've stated why - as is observably the case - there isn't some outcry in this case (or similar cases) in current society, I've noted certain age gaps can be a cause for concern hence they're not necessarily advisable, and I'm leaving it at that.
One last thing though, if you think this is somehow about dodgy locations and uneducated folks you're sorely mistaken. This happens at all levels of Western society to varying degrees which is part of why it's accepted. Final example. Friend of mine who's a (now) a senior director at a large company's young daughter (17 at time) rebels, leaves home and shacks up with an older guy (around 33 at time) for six years until she's 23. My friend's not happy, his wife isn't happy, but you know what? Nothing to be done. She's of age of consent, it's her choice even if my friend believes it to be poorly thought out and immature. Our social circle felt it was a case for concern in principle: but there was clearly nothing that crossed legal boundaries and to be fair to the older guy there was never any hint of abuse at all. Now I mention this example specifically because the girl involved is now 31 and I know her well socially as an adult via my friend and talking to her I know that there was never any abuse or other issue with the relationship whatsoever. She wanted to shack up with someone older. She wanted to annoy her father at the time. And she is of the view as a mature adult she had a good fun time and gained experience and life lessons faster than her peers who were dating 19, 20 and 21 year olds and she's perfectly happy with the decision she made at 17. Now honestly, what real position are you or I or anyone to prevent this and effectively impose what we want on to her and force her to not do something she wanted to do. At the end of the day you set an age of consent, you set rules for abuse and other behavior and so long as those aren't triggered then that's that. This happens and it's not uncommon and it's not just older guys taking advantage either. A percentage of younger women actively seek older men because they want that relationship. Sometimes it goes wrong and sometimes it's fine but either way it's realistically impossible to police which is why it isn't and it's also why, today as we seek to have more equality and diversity and after generations of rebelling youth you're not going to see much outrage if any at all just because an older guy (Walker in this case) dated some very young women without crossing any legal lines.