That's where you need to talk to those Dems in non-party terms. Talk to them about conservative/libertarian values and principles, get them to agree with you (as they do on many of those principles at least) on them and then start talking about how to put those principles into action. It won't be instantaneous, but loosening the grip of the party on them and getting them to make their own decisions on who and what to support is what we need to do in the long term. If we can get them to leave the party and go independent, that's a win too.
Many are too pig-headed to change. I have stepdaughters who are hardcore libs and pigheaded. For one thing, if I want to keep seeing my grandchildren I will not engage in arguments with them.
I used to be what was considered a liberal many decades ago. I came out of a Dem family and supported them for many years. It's like your team.
But as I got into my thirties I started questioning many Dem actions. I didn't think Reagan did that bad of a job. I liked his anti-communism, and I liked his Star Wars program. I couldn't understand why Dems would be against getting people off welfare, and what was wrong with having a strong military?
So when I changed parties during the Clinton admin many friends and family members were shocked. How could I dare vote for Republicans? Didn't I know they were all greedy b*stards who were only out for themselves?
I'd had enough of Dem policies by that time, and Slick Willy was not even a big time leftist....just basically a horny opportunist on the make.
I found out that people basically have to make the decision on their own. Getting into arguments and trying to convince them of this and that bad policy by leftist Dems won't work.
I like to get on neutral forums and challenge liberals on their actions knowing that many will refuse to reconsider anything they believe. But if you put out enough facts, some neutrals might eventually see the light.
One thing I believe is libs cannot be allowed to go unchallenged on neutral forums.