God said in the the bible-The wicked demands proof.
Prove all things; hold fast that which is good. (1 Thess. 5:21 KJV)
Obeying scripture is good, not wicked.
Only a fool doesn't demand proof, because many false prophets have gone out into the world:
Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world. (1 Jn. 4:1 NKJ)
Here is the text you are misinterpreting:
"A wicked and adulterous generation seeks after a sign, and no sign shall be given to it except the sign of the prophet Jonah." And He left them and departed (Matt. 16:4 NKJ)
Why is Christ correct? For two main reasons.
1 He's already did many signs Satan cannot do, like raise the dead. They asked for more signs, not to be convinced, but to accuse Him if He didn't comply.
2 Because we have scripture to test whether something is true or not.
Signs can be deceiving. The Lawless One will do "lying signs and wonders", that is, real signs that support lies:
The coming of the lawless one is according to the working of Satan, with all power, signs, and lying wonders, (2 Thess. 2:9 NKJ)
The false prophet will do lying signs, make fire come down from heaven to deceive those who dwell on the earth:
11 Then I saw another beast coming up out of the earth, and he had two horns like a lamb and spoke like a dragon.
12 And he exercises all the authority of the first beast in his presence, and causes the earth and those who dwell in it to worship the first beast, whose deadly wound was healed.
13
He performs great signs, so that he even makes fire come down from heaven on the earth in the sight of men.
14 And he deceives those who dwell on the earth by those signs which he was granted to do in the sight of the beast, telling those who dwell on the earth to make an image to the beast who was wounded by the sword and lived. (Rev. 13:11-14 NKJ)