Although the OP title question regarding Christianity and homophobia may be an unwarranted generalization, it does contain some truth, and that is; many Christians do feel their faith is anti-homosexual(ity), and agree with it, with quite a few people citing Biblical verse to support their belief. Right or wrong, this faith based homophobia does exist. Here's an interesting bit of information from Wikipedia.
"Historically, Christian churches have regarded homosexual sex as sinful, based on the Catholic understanding of the
natural law and traditional interpretations of certain passages in the
Bible. This position is today affirmed by most Christian groups, including the
Catholic (1.1 billion members) and
Orthodox (250 million members) Churches, part of
Protestant denominations, especially among
Evangelicals such as the
Southern Baptist Convention (16.3 million members), the
LDS Church (13 million members), and the
United Methodist Church (12 million members).
[31]
However, a small minority interpret biblical passages differently and argue that homosexuality can be seen as morally acceptable. This approach has been taken by a number of denominations in America, notably the
United Church of Canada (2.8 million members), the
United Church of Christ (1.1 million members), the
Moravian Church (825,000 members), the Anglican
Episcopal church, the
Anglican Church of Canada (800,000 members), the
Liberal Catholic Church,
Friends General Conference, the
Presbyterian Church (U.S.A.), the
Evangelical Lutheran Church in America and the
Evangelical Lutheran Church in Canada. Relatively great denominations had taken this approach in Europe like united, reformed and
Lutheran churches in
EKD (24.5 million members) in Germany,
Church of Sweden in Sweden (6,6 million members),
Church of Norway in Norway,
Church of Denmark in Denmark or
Protestant Church of the Netherlands in Netherlands (3,9 million members), reformed churches in
SEK in Switzerland, the
Methodist Church of Great Britain (330,000 members) and
Church of Scotland."
So, while not all Christians are homophobic and don't find support of homophobia in their faith or in the Bible, many Christians do. So the question I have as it relates to the Bible as a source of homophobia is, if this is not god's intention, why does this supposedly divinely inspired "word of god" lead so many astray? I know this is a bit off the track, but it does speak to the debate about properly interpreting the scriptures at issue.
And because some Christians
do contend there are anti-homosexual(ity) passages, the fact remains that it can be validly concluded that the Bible does speak against homosexual(ity). Their interpretation being no less right to them than the opposite interpretation is right to those who say they are wrong.
Therefore I think it's quite proper to raise the question the OP does.