"You are VERY ill advised to try and come between a man or woman and his / her beliefs. You chose your atheism over your family, or rather they chose God over your disbelief."
That's some pretty selective reasoning. The initial statement and the alleged inverse statement don't match. These would be the correct versions.
statement: You chose your atheism over your family.
inverse statement: Your family chose God over you.
statement: You chose atheism over your family's belief.
inverse statement: Your family chose God over your belief.
There's a legitimate difference. The second case is probably more likely to be true. Atheism and belief in god(s) are mutually and necessarily exclusive (under typical definitions).
The same cannot be said for the first case. Atheism/ theism and a relationship with family/ you are not necessarily exclusive nor mutual. It is a voluntary exclusion. Your family excludes a relationship with you unnecessarily as a matter of choice. You do not necessarily reciprocate this treatment. Unless you made an explicit statement that you have also disowned your family, it can't be logically inferred.
That said, you probably know your family pretty well. You may have known beforehand that being disowned would be a likely consequence of being open about your atheism. In that case, you made a choice and bear some responsibility for the outcome. However, this doesn't mean that you are at fault. If your family disowned you, they are the active party in causing harm. Since their actions were not a necessary consequence of your actions, but rather voluntary choice, it's logical to attribute fault to them.
Sorry if I'm rambling a little nonsensically.
More to the point, even if it is true that you bear some responsibility for the outcome, that person is trying to shift blame, which is utter bullshit.
I assumed it was something along those lines.