I guess it's all about context:
11 For what man knoweth the things of a man, but the spirit of a man that is in him?
So the things also that are of God, no man knoweth, but the Spirit of God.
12 Now, we have received not the spirit of this world, but the Spirit that is of God: that we may know the things that are given us from God.
13 Which things also we speak: not in the learned words of human wisdom, but in the doctrine of the Spirit, comparing spiritual things with spiritual.
14 But the sensual man perceiveth not these things that are of the Spirit of God. For it is foolishness to him: and he cannot understand, because it is spiritually examined.
Don't quote me 13 and 14 without 12.
We are imbued with the Spirit that we might understand spiritual things. Yet even then it is still our choice, having such understanding, to continue to sin.
There are two classes of people referred to, the natural man and the spiritual man, the man with the spirit and the man without it.
Verse 12 doesn't say everyone has the Spirit. That is limited in context to believers.