Actually, asking other people to spam report someone is harassment. Even if you said "Good game everyone, honors for everyone. Oh, and report Zilean" it is a punishable offense because of asking them to report for you. What you quoted was not necessary to validate the report.
You don't even need to ask others to report. 9 reports in a single match mean no more than 1 does. The match will be flagged to check their behavior with just one report; eight more won't make the system check any harder.
Now that you know this, I'm sure you realize why it does no good to ask for reports. But it also does harm. It antagonizes the player and is nothing less than bullying even if your report is valid.
Furthermore, it takes way more than one game to get punished (except in extreme cases). You would've had many games of toxic behavior that lead to this chat restriction, not just the one; reform cards merely show you your most recent contributing logs, not all of them.
If you have any questions, please ask. Keep it civil though, because I'm here to help.
