My personal opinion is that the kids should be allowed to call their steps what makes them comfortable and happy - whether it is their first name, or mom/dad, or another term that they come up with. I know some kids who have a special name for their step, so that they can express their love and attachment to that person without the loyalty bind of the term "mom" or "dad". My stepkids call me by my first name. At one time they were calling me "mom", but their mom had a complete meltdown about it, so they went back to calling me by my first name. I never asked them or expected them to call me mom, they just did on their own after about 3 years. But, they're not required to do it - and it doesn't bother me if they don't.
I know a lot of people will say that a child should never call a step "mom" or "dad". I personally think this is a bit territorial, but I understand where that comes from. Especially if there has been alienation. When I was growing up I was very close to one of my friends, and we spent a lot of time at each others houses. I called her mother "mom" when I was at their house, and vice-versa. This wasn't out of disrespect for our own mothers - it was because we saw them as our collective moms, so to speak. I give this example because I think that, often times, kids who have a close relationship with their steps will refer to them as "mom" or "dad" because that is the relationship they have with them. I don't see anything wrong with that and I think forbidding a child to do it if that's how they feel about their step is to deny the importance of one of their primary relationships. That's a disservice to the child.
However... the situation with twistedmama is slightly different. What I find problematic about that situation is, as Kitty has already addressed, that he refers to his real father by his first name. That should never happen. Never should a child call a step "mom" or "dad" and then refer to their biological parent by their first name. That smacks of replacement, and I don't blame the father at all for being upset. The message that is sent to the child when they are taught, encouraged, or allowed to do this is that their bio-parent is unimportant, lacking somehow, undeserving of their love or respect, and so on.
So the issue here isn't so much that the child is calling the step "dad". The issue is that the child is calling the step "dad" and then referring to his real father by his first name. The rule should be that it's ok to add, but never to take away. A step does not replace the real parent. No matter how great the step is, or how bad the bio-parent is, it's not a replacement. Ever.
Just look at kids who have been adopted. They grow up (usually) never knowing their bio-parents, or forming any kind of bond with them. In many cases, even when they have a strong bond and loving, supportive relationship with their adoptive parents, they still grow up wanting to know their real parents, wanting to find them, wanting to have a relationship with them. That speaks to the fact that the biological parental bond is transcendent, and that it can't be ignored or replaced. Why do some people believe that their children will be "fine" without the other parent in their lives, or that they can just replace them with another parent of their choosing? In my mind it's selfish and makes no sense whatsoever. People who do that are just hurting their own children for their own selfish reasons.
