Thank you for replying. So i guess the old tutorial of getting a thornmail on Ashe has some merit ehh? Thing is, I've looked at this person's history and noticed that there are many games where this player builds normally and often wins. Also I don't think this person would reach plat 5 with this strategy as an ADC. As roles are important, an adc's role is to deal damage. Often a defensive item is built later in the game but as first item, it dramatically reduces your ability to perform your role. Also building a frozen mallet on a character which already has a built in slow is just inefficient and further reduces this player's ability to perform their role.
The point being here is that a plat 5 should also know how to build and how to perform their role. It's established from looking at the player's match history (which you probably haven't) that this player didn't get to plat 5 from building this this way. The latest match was where two defensive utility type items like this are found though. It seems this person is just getting bolder with each game as no action has been taken against them.
Also, I'd like to point out that this player has not had any success in their games with this strategy, therefore it stands to reason that this player would stop their behavior as the reward of winning games is not there. So it stands to reason that this player's reward for this continued behavior is something other than winning games. Most likely trolling as this player definitely knows of better strategies to use.