Disclaimer: I know I sound condescending on this. It is not meant that way. The information I give you, is because I like people knowing whats going on. Take this rebuke of your statement in the spirit of this discussion, and not as an offense.
but I could be misinterpreting it.
You are not misinterpreting it, but you don't have all the information.
Which isn't your fault btw. Riot did a pretty slow job at communicating in this case.
Here is the thourough response by Riot Gromp on the matter.
Here is the centerpiece of the response you should look at:
To be clear,** this player does attempt to communicate intent and strategy, but a good chunk of teammates across hundreds of games just don’t want to sign up for the plan.** That lack of agreement on the new plan makes for a pretty chaotic game and leads to a huge share of this player’s reports. If a teammate in champ select says, “pls no, this is game 5 of promos”, maybe stick with something conventional and skip tilting your teammates off the face of the earth. In short, argue for your idea, but stay ready to be flexible.
So the problem is not a lack of communication.
The problem is that he wanted to play something completely off meta, in a team of randomly assigned people, who all want to play according to meta. Yes he communicated, but he ignored it when they said "NO."
Hope this clears things up a bit on the Singed matter, and puts this argument to rest.