see, this is actually a good example of the pitfalls of understanding hierarchy through the prism of identified groups, rather than through the prism of class.
it was true, in the twentieth century, that seniors were at a relative disadvantage in society, as each successive generation on this continent continually increased it's share of the wealth. that was a constant up until the 70s. see richard wolff as one good source on this topic. but, the fact of the matter is that, since that relation has flipped, wealth has actually begun to correlate with age. - and, in today's society, seniors are actually the people with the most amount of wealth, influence, property and power.
so, a rule that allows for age discrimination in order to benefit seniors is absurd. "seniors only" restrictions are now protecting the most advantaged and most privileged group in our society. if the idea is that discrimination is ok when it protects a disadvantaged group, that group is no longer the elderly, but the young - and the discounts should be provided to millennials, instead.
as of right now, it feels like seniors have simply legislated themselves above the law.
fifty years from now, the situation may reverse itself, again. and, we're left with a constant we should have realized in the first place - we should have focused on class all along.
the idea of seniors-only housing in 2018 is not a tool to help the disadvantaged, but a means for the wealthy to keep the poor away.
http://www.ohrc.on.ca/en/policy-discrimination-against-older-people-because-age/4-general-principles\