Unfortunately, sometimes people abuse their role as a family member on the basis that they are "related." Just because people are related by blood does not mean that we are guaranteed to love them. Of course, it would be wonderful if we did have great relationships with those who are related; however, this does not constitute constant forgiveness for misbehavior committed by the relatives. For clarification, everyone makes mistakes and there is always the possibility for relationships of any kind to turn toxic. The issue arises when family members use their blood relation as an excuse to manipulate the person whom they are being toxic toward. This is, by no means, ever acceptable.
Holding blood relations over somebody's head is incredibly inappropriate. Ideally, one would hope that your relatives are not toxic, but we know that the world is full of surprises and humans are highly variable and extremely unpredictable. Sometimes, relatives are toxic. The situation only worsens when they refer to themselves as being your "blood relative" which is merely their way of trying to keep you involved in the toxicity by making you feel guilty for removing yourself from the negativity. This is not a healthy way to either solve an issue or accept that there is an issue. Instead, it places this invisible shackle keeping you and this other person bound together for life simply because you are related. If the relationship was healthy, then there would be no problems; yet, when there is a party who is clearly abusing how they treat you, then there is a major problem.
It is okay to remove toxic people from your life for the purpose of your mental and physical safety.
It is also okay if the toxic people that you are removing from your life for the purpose of your mental and physical safety are related to you, even if it is "by blood."
There is no excuse for hindering the wellbeing of other people, especially when you are related. It can be challenging to recognize that people who we "should" be able to trust sometimes are bad influences in our lives. I totally understand. Realizing this can be shocking, but you should also recognize that we deserve much more than being forced to keep people around who are hurting us based on the rationale that they are "blood relatives."
Acknowledging when something is unhealthy takes a lot of courage and thought for determining how to handle it. And for the record, the single factor of blood never constitutes love, respect, or relationships. Ever.