There are worse things than forgetfulness, and discounting the entirety of the medical field for a second, ways people can convince themselves of anything, particularly for an event they find harrowing or traumatic. Like I said to others, if you want to fixate on that, go for it. But the other things that were claimed to be lies, aren't. There may be a distinction between a Vietnam veteran and a Vietnam-era veteran, but it's a relatively fine distinction to make when people here regularly go on long, long tangents about how things might not be racist and you don't need to read into things so negatively.
This is what I was trying to illustrate - peoples' judgement of Phillips, but not the teenagers, comes down to making a choice in that regard, to alter their level of criticism based on the person they're criticising. This doesn't work in the reverse, and there's a thread on it so I don't want to touch on it too much, because the hat is a visible, surface-level thing that can be debated. Phillips' past, and truthfulness, are deeper than that, and rely on things being dredged up from years past, or in the cases I've seen in this thread, flat out willfully misinterpreted.