Lichess message tells me I accused someone of cheating - But I did not!

I have just received a Lichess message tells me I accused someone of cheating - But I did not!

I played in a rapid rated tournament and someone said that a player xyz was cheating. I wrote in this tournament chat something like "Well, report this player then. But are you sure he cheated?"

That's about it. Next thing - Lichess tells me off with a warning. WTF?!

You can discuss about a warning you received here : lichess.org/appeal#help-clean-warning

Also don't report a user just because someone told you to do it.