They gave out medals in the late 60s and early 70s in Vietnam like candy because it was at that point an unpopular war and they wanted to keep up morale. Kerry still got turned down for one of his purple hearts and got it when he got a new CO and put himself in for it again.
Getting three purple hearts without missing a day of service and then using it as a technicality to get out of Vietnam in only 4 months was cowardice, not heroic. One of them for shrapnel from his own gun which he got by screwing up.
Then he went on to testify that he and most Vietnam vets were war criminals and they lived every day every story he'd ever heard, he said he threw his ribbons that he still had over the white house fence. He perjured himself and said that he'd personally seen the US enter Cambodia. Kerry was a liar and a fraud. The left believe he's a hero because he says what they want to hear, not because of anything he did in a war.
In the Navy, if you survived Mess Call you could be considered for a Medal. Especially if they ran out of Ice Cream. That was goddam near reason for mutiny.
Viet Nam was a ground War. There weren't any Vietnamese Battleships. Or Aircraft Carriers. Or Submarines. Or Destroyers or Cruisers.
The Navy was a fringe player relegated to close air support for Marines and the occasional Haiphong run.
SEALs....? Nobody saw them doing what they did. Kinda tough to put yourself in for a Medal without witnesses. Not picking on SEALs. Damned fine troops.
John Kerry? A scumbag, a liar, a traitor and a coward