I can't hear the video, however, there were few times Jesus mentioned taxes. One was Capernaum, where those who took up tribute money asked Peter if he paid the tribute.
Matthew 17:24 And when they were come to Capernaum, they that received tribute money came to Peter, and said, Doth not your master pay tribute?
25 He saith, Yes. And when he was come into the house, Jesus prevented him, saying, What thinkest thou, Simon? of whom do the kings of the earth take custom or tribute? of their own children, or of strangers?
26 Peter saith unto him, Of strangers. Jesus saith unto him, Then are the children free.
27 Notwithstanding, lest we should offend them, go thou to the sea, and cast an hook, and take up the fish that first cometh up; and when thou hast opened his mouth, thou shalt find a piece of money: that take, and give unto them for me and thee.
Another was in Jerusalem, when the Pharisees tried to trick him.
Matthew 22:15 Then went the Pharisees, and took counsel how they might entangle him in his talk.
16 And they sent out unto him their disciples with the Herodians, saying, Master, we know that thou art true, and teachest the way of God in truth, neither carest thou for any man: for thou regardest not the person of men.
17 Tell us therefore, What thinkest thou? Is it lawful to give tribute unto Caesar, or not?
18 But Jesus perceived their wickedness, and said, Why tempt ye me, ye hypocrites?
19 Shew me the tribute money. And they brought unto him a penny.
20 And he saith unto them, Whose is this image and superscription?
21 They say unto him, Caesar's. Then saith he unto them, Render therefore unto Caesar the things which are Caesar's; and unto God the things that are God's.
22 When they had heard these words, they marvelled, and left him, and went their way.
Neither one can be taken to mean a flat tax unless you want it to mean a flat tax.
However, Jesus did teach that to love money was the other master to loving God.
Matthew 6:24 No man 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.
25 Therefore I say unto you, Take no thought for your life, what ye shall eat, or what ye shall drink; nor yet for your body, what ye shall put on. Is not the life more than meat, and the body than raiment?
26 Behold the fowls of the air: for they sow not, neither do they reap, nor gather into barns; yet your heavenly Father feedeth them. Are ye not much better than they?
27 Which of you by taking thought can add one cubit unto his stature?
I didn't even watch the Prayer breakfast, but if Obama looked at him funny, probably because he thought it was inapropriate to bring political disscussions to a prayer breakfast. But typically conservative in some groups.
(lost my spell checker)