First of all, let me assure you that Mom and Dad read and reread and talk and agonize over every word you write. They may not respond, being at a loss as to how to communicate effectively, but they do not ignore what you say.
Anyway, I had some thoughts on the matter, and will let you decide if my attempts at communication are effective. :)
We - your relatives who have reached out to you, and probably many others - value you as a person, even when we disagree with you. I, personally, would like the opportunity to show you that I care about you (and I assume the same is true for the others, but do not claim to speak for them). Our shared history (not to say, necessarily, our blood relation status) seems to me to be a claim at least as strong as that of location. That is to say, if you can "put politics aside" - not to deny your values, but to choose to find common ground or non-controversial topics of conversation - for the sake of a neighbor or co-worker, could you not do the same for your extended family?
If I thought someone was claiming a "right" to my time, money, and company, I would probably be somewhat irritated. However, on further consideration (as regards Mom, Dad, and Granny), it does appear reasonable for them to feel that way. They have given so much of their time, money, and company to me (and you) that they really do have a right to expect some return on the investment.
I feel like there should be a concluding paragraph here, though perhaps I have said enough for the present.
Still loving and praying for you,
Anyway, time to get a couple other things done.