This is a rather odd statement...
I would argue the point that playing and winning are the same in that context.
Not at all.
Are you inferring that there are people who play this game and want to "lose"?
Nope, not even close.
Those who focus to much on the "play to win" style have a lot of trouble enjoying the game itself, outside of the combat aspects. To them, anything else is irrelevant. (Thecasualoblivion is obviously one of those. The only thing that matters to them is optimized play - specifically optimized for combat, anything else if foolish and/or incomprehensible to them.) Basically they need a clearly defined goal to measure themselves against, and achieving that is how they win, and anything that doesn't contribute to achieving that is a waste of time. People who don't focus on achieving the goal are either foolish, or deliberately wasting their time. They also tend to be rather selfish, in the sense that they want their character to out-perform other characters in combat. 5e makes it harder to dominate a combat with a single character, so they don't enjoy it as much.
Those who want to "play" the game generally consider combat a secondary concern. They want to socialize with NPC's, solve puzzles, explore new areas. They actually pay attention to the DM when a new area or city is described, instead of interrupting to ask for a perception check so they can see if there is anyone waiting to ambush them. They want to develop their characters and be part of a story, not just a series of XP and treasure generating encounters.
You also have those RP types who can't or won't build a combat functional character, and the rest of the group has to carry them through combats. They are almost as bad as the "my characters are optimized death machines with no personalty" players.
Most people can switch between the play styles as needed - their characters can contribute in combat (they may not be super-optimized but they hold their own), but they also contribute outside of combat. Their characters have personalities and stories, and can do things aside from kill better and faster. They aren't just combat monsters with no social skills, or the minimum social skills needed to meet the expected requirements of the module so they can get to the next combat. Unfortunately, most "Organized Play" situations involve pre-written scenarios with a set number of combat encounters and non-combat encounters that have to be completed within a 4 hour or less time frame. And the social encounters have no impact or relevance after the game session is over, but the combat has lasting rewards in the form of XP and treasure. By it's very nature, Organized Play favors combat optimized characters. That is not necessarily the case with home games - the DM has vastly more agency and control of the flow of the game. They tend to be more free form, and straight combat may be much less important than your characters out of combat decisions and actions.
The "Play to Win!" players tend to do much better in Organized Play situations (because the goals are clearly laid out and heavily feature combat), and 4e was also designed to cater to that playstyle. 5e has Organized Play with the Adventurer's League, but really shines in the home games. The rules are simpler and more streamlined so it's harder to come up with "game breaking" builds that make other players irrelevant.
Powergaming isn't a bad thing in and of itself - I optimize my characters all the time, because I want them to do interesting things in combat or out of combat. And being useless in combat doesn't feel good to me. But just like anything else, if you take it to an extreme it's not good or healthy for the game.
