First and foremost, Bernie is the only person in this race who I actually trust. I voted for him, and will absolutely do so again should he be the nominee. I'm just calling 'bull' where I think it's due - while I 100% believe he believes in his cause and thinks his goals can be accomplished, realistically I think he'll face tons of resistance.
The thing about logic is that everyone seems to have their own version of it. You'd think it was supposed to be an objective sort of thing, but, actually, pure logic is employed very scarcely in subjects other than math/programming/etc. Most positions - including mine - are based in personal values. In my case, I assume that everyone deserves equal treatment and rights to the greatest extent possible that does not infringe upon the rights of others. In cases of conflicting candidate rights, I tend to defer to compassion and favor the inclusive one. Since other people's underlying values, which, (like mine) are almost never swayed by reason, frequently fail to match with my own, we effectively end up talking at cross purposes and getting nowhere. That's why I prefer empathy as a means of persuasion.
In some cases, rights are "abundant". For instance when one couple gets married, that doesn't exhaust any "available marriage" resource such that others don't have enough to do the same. Material wealth, sadly, is not abundant. Feel free to portray measures to lessen income inequality as an attack on the rich, but that perception would actually be borne out of a different evaluation of the fairness of chance. I certainly don't claim to speak for other liberals, but I personally view chance as being in diametric opposition to fairness. Some people end up being screwed over and others thriving in large part because no reason. A huge percentage of Bernie's talking points are focused on measures to reduce the influence of chance. On the other end of the spectrum, many conservatives seem to view chance in the light of opportunity. And it's true, opportunity is a factor. The trouble with that is that opportunity also isn't available to everyone. Some people just get unlucky and have no good recourse under the existing system. I (and I imagine many other liberals) value their right to have their basic needs met over the right of the very rich to buy that twentieth limousine.
And, yes, some liberals do get upset with systems that allow, say, stock brokers to make tons of money without really contributing anything of value in return. Many of them (even Bernie!) may go too far and claim that those brokers disobeyed the law when they didn't. People are prone to overreact. However, in Bernie's case, as far as I'm aware no suggestions to actually prosecute people for actions that were legal at the time are being made. He just wants to change the rules going forward.
The whole "religious liberty" debate is basically the same issue in a different mask. Some people happen to have sexual orientations and/or gender identities that provide a de facto disadvantage in our society. Many liberals want to level the playing field, while some conservatives would like the right to push LGBT people away because they haven't taken their "opportunity" to fall in line with religious beliefs. So the question becomes whether the "unlucky" ones have to stress over which stores they're allowed to shop at so business owners can retain the luxury to not deal with people they don't approve of. Are all people's rights important, or only the rights of the "lucky" ones?
The thing about the whole voting for Cruz issue is that, while I can't judge what's in your heart, in the grand scheme of things it also doesn't particularly matter what's hiding in there. You may legitimately believe that LGBT equality is important, but by supporting someone you know will try to revoke those rights, you are in effect opposing their existence, and how you feel about it just doesn't come into play. It's what you do that defines you.