Non-sequitur? He gave money to support a proposition that upheld society's longest existing institution against an onslaught of hyper-liberal hand-wringing. Your ad hominem of homophobe is applied to anyone who happens to agree with the current gay agenda of establishing a protected class with special rights and accommodations.
It is only through the flooding of the airwaves with propaganda and brainwashing of ignorant youth that same sex marriage has gotten the marginal support that it has. Surely it will grow, since the formative years of children are now filled with misinformation campaigns regarding homosexuality and its classification as an inherent trait similar to color or ethnicity that should be celebrated and honored.
In the meantime, there are still many people left who were not recipients of such "special education" and who have respect for the idea of marriage. Everyone has the same inherent right to marry. A male who has reached the age of consent may marry a female who has reached the age of consent, as long as they are not related too closely and meet the other requirement of not having a living spouse (and vice versa). These are not harsh restrictions, and they apply equally to all people. Note that there are no requirements to love one another, though presumably this should be the primary reason why the two would want to be wed.
Eich supporting these normal restrictions, as loose as they are, on marriage is not an act of discrimination.