McAfee seems to be a bit oversensitive with gaming sites. Recently they have started flagging Party Poker software too.
I guess the gaming softwares are not saints either. Since they have the opportunity, they must be scouting/monitoring the players’ computers for usage of competition – e.g. XyZ casino checking whether the player plays at other casinos. If this is true McAfee or other antivirus can’t be blamed for flagging the gaming softwares.
Disclaimer – This is however my personal 
feeling, without any prejudice against any operators.