Stupidity of changing definition of marriage

Gay activists often argue that changing the definition of marriage will give them more rights and equality. That on the surface sounds good but after a bit of thinking I realize how ridiculous it really is. Here is an analogy to make it clear.

I for one oppose affirmative action based on race because that takes away rights and equal treatment of poor/disadvantaged white people. So the proper approach to correct this problem is to revisit how we administer the affirmative action i.e. make it need-based not race-based i.e. anyone regardless of color should be able to receive help if he/she is disadvantaged socially and economically. But if someone tells me there is a quicker way to correct the current affirmative action laws by changing the definition of the phrase "colored people" to include white people because white is technically a color so white people should be also classified under the phrase "colored people" therefore they will be automatically included in the current race-based affirmative action laws since they are also "colored". I would say " what the heck are you thinking? what ? no, this is a stupid short cut instead of a thorough fix of the problem. If we change the definition of colored people to include white folks then what is the point of having the phrase colored people? ie. why don't we just say "everybody" instead of colored people then? This is a ridiculous idea". Well, it's the same thing with gay marriages. Currently family benefits are administered based primarily on marriage that indeed exclude others from getting equal rights in some cases. We need to thoroughly review how we give out family benefits such as giving social security benefits not only to surviving spouse, but maybe also to domestic partners, or even sibling partners (e.g. 2 old sisters who never got married to anyone and they live together to support and depend on each other. They are not emotionally or sexually engaged so they are not civil unioned but they are a form of plutonic partnership and I think they should be able to get each other's social security benefit should one decease). As you can see we should review and change the way to administer benefits. However, it is plainly a stupid idea for gay activists to say there is a quicker short cut by changing the definition of marriage to include gay couples. This does not solve the problem (i.e. the issue of 2 old sisters metnioned above would still be unresolved by gay marriages and they will still be discrimated and excluded) and if we change the definition of marriage to include gay couples, then what stops others from continue to change the definition of marriages? Changing the definition of marriage to include gay couples to get equal family benefits is as ridiculous as changing the definition of the phrase "colored people" to include white people in order to get equal benefits under affirmative actions. Gosh, liberals think they are all smart but not really. They are cows who don't think for themselves.