When we hold negative ideas and beliefs about a group of people we don't know, that's called bigotry. When this bigotry is based on race, it's called racial bigotry, or 'racism' for short. An example of racial bigotry would be the belief that black people are not as intelligent as people of other races. That they tend to be lazy, sexually promiscuous, and more inclined toward immoral and/or criminal behavior.
When these kinds of bigoted beliefs include a desire to oppress, restrain, punish, or otherwise harm the people they are being applied to because of their negativity, then it becomes a hateful expression of that bigotry. For example, the desire to deliberately oppress black people because one believes they are especially ignorant, lazy, promiscuous, immoral, and given to criminal behavior, is an expression of, and would rightly be referred to as 'racial hatred'. The idea, for example, that we would need a special law forbidding a black man to associate with white girls, unsupervised, because we fear he would not be able to control his lust, would be an expression of racial hatred.
The current bigotry being held and expressed toward homosexuals is no different than the racial bigotry of the past except that it's based on a person's sexual orientation rather than on one's skin color. Just as with racial bigotry, it's based on falsely held negative ideas and beliefs about a whole group of people that the bigot doesn't actually know. The belief that homosexuals are inordinately immoral, promiscuous, disease-ridden (or at least disease-prone), anti-social, and even criminal, are examples of contemporary bigotry against homosexuals. Homosexuals are no more immoral, promiscuous, diseased, anti-social or criminal than anyone else is in our society, just as black people are no more ignorant, lazy, promiscuous, immoral, or criminal than people of any other race, are. Yet these bigoted beliefs persist, nevertheless.
And when this sexual bigotry finds expression in a desire to oppress, restrain, punish, or otherwise harm homosexuals, it becomes a form of hatred. The fact that the bigot believes that a homosexual can choose not to be homosexual and a black person cannot choose not to be black, has nothing to do with anything. The bigotry is in thinking that homosexuals are inherently bad, not in whether or not one can choose to be homosexual or not. And the hatred is in the desire to harm homosexuals for being homosexuals, not in whether or not they can choose not to be what the bigot believes them to be.
Reading this, the bigots and haters will, of course, try to defend their hateful beliefs using facts which they imagine apply to all homosexuals, and on conclusions they imagine to be based on what's good and necessary for the health of society. But this is no different than the racial bigots and haters of years past who also argued with their facts about how dark-skinned people really are less intelligent, more promiscuous, morally weak, and given to criminal behavior than people of other color skin, and so for the good and safety of society, needed be legally and socially more intensely restrained.
But these facts will have been 'cherry-picked' by the bigot to support the negative beliefs they already hold, and when they're presented with facts that contradict their bigotry, these will be ignored, denied, and refuted in favor of the bigots beliefs. And it's exactly this defensiveness, rather than a balanced, logical, and open-minded reaction, that gives the bigotry away. Bigots believe as they do because they want their negative beliefs to be true. And so they will defend these beliefs whenever they're challenged, rather than re-examine them as a reasonable, unbiased, person would do.