1) Marriage is, by definition, whatever we define it to be. Different versions of the bible use words with different definitions; is one or the other correct? And language changes on a daily basis; to insist we keep our language ancient because the language is somehow truer than reality? You must speak Latin.
Incidentally, using a seperate system, the 'civil union', would be less cost-effective, since it requires more man-hours in legal revisions. Not that money's an issue.
2) Because why? You say this, yet it isn't true: those of a generation or region where exposure to the queer population is high end up being more accepting of everyone, as people, in general. Tolerance becomes learned, advantages are exchanged. The educated college-age generation, the generation in whose hands your entire senior livelihood rests, was brought up in a world where it was not nearly as "wrong" to be gay as you remember. You cannot stop this, because it contributes to world good.