I would answer them by saying that they are covetous Pharisees.
Luke 16:13-14 No servant can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon. 14 And the Pharisees also, who were covetous, heard all these things: and they derided him.
Then I would tell them that they cause division and serve their own belly.
Romans 16:17-18 Now I beseech you, brethren, mark them which cause divisions and offences contrary to the doctrine which ye have learned; and avoid them. 18 For they that are such serve not our Lord Jesus Christ, but their own belly; and by good words and fair speeches deceive the hearts of the simple.