Is it obligatory to condemn chess players if the game is free of prohibitions, or is it permissible to leave them be, taking into account the scholarly disagreement regarding its ruling?

Playing chess is a matter of scholarly disagreement. The majority of scholars hold it to be forbidden, while the Shafi'is do not consider it forbidden. It is not obligatory to condemn someone who plays it believing it to be permissible, due to the absence of an explicit text or consensus prohibiting it. However, if one plays it believing it to be forbidden, then it is obligatory to condemn him. If he believes it to be permissible, then it is not permissible to condemn him, unless his justification is extremely weak.