Jesus never mentioned homosexuality. Why are you and other fundamentalists Christians so obsessed with it?

There is a widespread assumption among prohomosexual theologians that Jesus never said anything about homosexuality in his teachings. Time and time again, like a broken record, unsuspecting gays blindly repeat "Jesus never once said anything about homosexuality." This type of "compartmentalization" of the Bible serves these religious pundits in two ways:
1. It bolsters the erroneous and illogical argument that silence equals consent.
2. If Jesus didn't have a problem with gays, then why should anyone else?

First, Jesus didn't had a problem with people, he had a problem with sin, which was the very reason he came to die. Since homosexuality is one of many sinful expressions of sexual choice it is then understandable that whenever Jesus spoke about sin, it was inclusive of the homosexual condition.
Secondly, Jesus specifically affirmed the moral mandates of the  Old Testament which forbade homosexual expression among many other things such as incest, sex with animals, and cross dressing. He did not address dietary, rituals, clothing or similar laws because those were unique to people of Jewish descent, but the moral laws were applicable to both Jews and Gentiles alike. As a matter of record he openly broke certain types of laws to show that he was not concerned with traditions. Yet, he never once encouraged nor participated in breaking a moral law (Hebrews 4:15).
In Matthew 19:3-9, when asked about divorce, Jesus responded with a sweeping condemnation of all relationships except those which met the original intent. This was one man with one woman for life.

The attempts of misguided sexual politics of such theologians to divorce Jesus (as a singular operative) from God or the Bible fall way short of true biblical interpretation. Any simple study of the scripture will show that  Jesus is God (1John 4:23), Jesus is the Word (logos) made flesh (John 1:14) and ALL scripture is given by inspiration of God (2 Tim 3:16). There can be no separation of the critical and fundamntal truths when determining the veracity of Biblical teaching.

As to your accusation of "obsession", I would rather call it passion. Christians who believe homosexuality to be destructive to the continuation of the family and the social structure have a constitutional  and biblical right to express such views as openly as they choose.

Hasn't the Bible been misinterpreted by homophobes who want to deny gay men and women the right to love each other in faithful, monogamous relationships?

If we were to accept your premise as truth, then Jesus himself would certainly be the greatest "homophobe" who ever lived!  No one argue that the Bible has been used as a tool to lend credence to ungodly human activities. But that nothing to do with the Bible and what it says and everything to do with people and their own misguided use of the Bible.  Gays and lesbians may find satisfaction in relationships, but there is no spiritual justification for such relationships.
Additionally, the Bible was written to individuals who CHOOSE to follow Jesus and willingly submit their lives to his Lordship. As such we lose our "rights" to follow our own desires. Jesus said, "If any man would follow me, let him DENY himself , take up his cross and follow me."  Therefore if anyone takes upon themselves the oxymoronic term "gay christian" , they are in conflict with Christ's basic directives. One cannot hold on to a sinful identity and claim to follow him. There is no Biblical model, supposition, nor encouragement for homosexual relationships regardless of the context of the relationship.
Love is simply not synonymous with sexual expression, rather sexual expression is a derivative, a benefit of the divinely sanctioned love instituted by God the creator in the beginning.

Is it okay to have homosexual thoughts?

According to the scriptures, we should "demolish every (my italics) argument and every pretension that sets itself up against the knowledge of God" and to "take every thought captive to make it  obient to Christ." (2 Cor 10:5 NIV) What the Bible cautions against is allowing a pattern of sinful thoughts to take root (Rm 6:1) which causes a hardening of spiritual sensitivities. It makes no distinction between heterosexual or homosexual thoughts, but equally instructs all Christians that such thoughts are wrong. Any wayward sexual thoughts which are allowed to sit and fester have the ability to develop into full fledged sin (supremacy over Christ in your life), so we must take offensive steps to bring them into subjection. For more insight of the progression of a sinful thought read James 1:14,15.
The Bible never says or suggests that wrong thoughts will not present themselves, but rather focuses is on what to do when they do present themselves.

If you want to overcome homosexual thoughts, the key is to be "transformed by the renewing of your mind." (Romans 12:1,2) Each of the words "transformed" and "renewing" signify the continuation of a process in the mind, will and emotions. These thoughts must be cast down with praise, worship, prayer and meditation of God's Word. Of course this is predicated upon a relationship with Christ.