Because this happened to them. They were TEMPLE Priests for the most part, the Pharisees and the Sadducees. That put them as front line members of this battle, here, because they handled the WORD of God and when anyone does that, this happens:
Mark 4:15
And these are they by the way side,
where the word is sown; but when they have heard,
Satan cometh immediately, and taketh away the word that was sown
in their hearts.
When you read of men such as them, you should have an awareness of what happened to them INTERNALLY. Upon the entrance of Satan to steal and to blind it is no longer just the question of the individual, but the individual and THE THIEF/ROBBER who entered them.
If you see only Pharisee as an individual you will miss his CAPTOR and mistake the individual as being the child of the devil when in fact they are captive to same, as all blind men are.
And I might say if we read and MISS the other party, that such sight has already been blinded and mistakes the man for the devil.
The beast is a bit more interesting of a subject, but yes, there is a sure connection to Satan in the matters of the beast without any doubt. We know for example that the Harlot of Babylon, that woman, rides the beast. We can also see that where she sits is here:
Revelation 17:15
And he saith unto me, The waters which thou sawest,
where the whore sitteth, are peoples, and multitudes, and nations, and tongues.
There, where the whore sitteth are PEOPLE.
These would be the PEOPLE who have their MINDS blinded to the Gospel by our mutual adversary, the god of this world, Satan.
These matters can get very progressively complex. It's important to establish the components to every parable. For that I point to Jesus in Mark 4 where He says to understand ALL parables, and in this I would include allegories as well, it's important to get the basic components to the account in order to establish legitmacy of any dissections.
The basic components to understanding any parable are these.
God, Satan and people.
And to that I would generally agree as well. Just like the Pharisees, the christians are also on the front lines of the battles today, SO it is likely to conclude in the fact that the headliners of INTERNAL DECEPTION will be 'in the churches.'
If we look at the preamble of Jesus in Revelation to the SEVEN CHURCHES, the WORKS AND WAYS OF SATAN are addressed therein to ALL of them.
When we are heeded to LISTEN to the Words of the Spirit we must each individual take those Words we don't like PERSONALLY. We all tend to insulate ourselves automatically from the BAD WORDS and say to ourselves, 'these don't apply to ME.'
When we do, we have already violated Jesus Commands to LISTEN:
"He that hath an ear, let him hear what the Spirit saith unto the churches"
When we DON'T hear the words we DON'T like and say in our hearts, 'these don't apply to me because....'
we are not hearing,
but we DEFRAY those Words away from our sweet old selves.