A believer: Yesu the JW teach Jesus is our mediator
http://wol.jw.org/en/wol/d/r1/lp-e/2008922
It does seems like it, indeed, at first sight. But you have to read closely.
“The Mediator of a New Covenant”
11, 12. How is Jesus’ role as Mediator unique?
11 Read 1 Timothy 2:5, 6. Jesus is the “one mediator between God and men.” He is “the mediator of a new covenant.” (Heb. 9:15; 12:24) However, Moses is also spoken of as a mediator—the mediator of the Law covenant. (Gal. 3:19) How, then, is Jesus’ role as Mediator unique?
The mediator of a New covenant.
Who is in the new covenant? If you search on JW.org for the new covenant, you see it is only the 144.000.
To go further with the link you provided:
13. What is involved in Jesus’ role as Mediator?
13 What does Jesus’ role as Mediator involve? Well, Jehovah applies the value of Jesus’ blood to those being brought into the new covenant. In this way, Jehovah legally credits them with righteousness. (Rom. 3:24; Heb. 9:15) God can then take them into the new covenant with the prospect of their becoming heavenly king-priests! As their Mediator, Jesus assists them in maintaining a clean standing before God.—Heb. 2:16.
Jesus assists them. To whom does their and them refer? To the heavenly king-priests in the preceding sentence. And who is going to be a heavenly king-priest? It is the 144.000. As their mediator, can consequently be rephrased as: As the mediator of the 144.000.
What about those who are not in the new covenant, those who hope to live forever on earth, not in heaven? While not participants in the new covenant, these are beneficiaries of it.
Those who are not in the new covenant. Well, if you are outside of this new covenant, if you not have the heavenly hope, Jesus is not your mediator. You are no participant
Do you see? It is very important to examine this more thorougly than just quickly reading this text.