This is perhaps because we mentally reserve the nominative case for subject heads only.

这可能因我们在心理题负责人保留了格。

The pronoun " She" is in the nominative case, marking it as the subject or giver.

代词“她”格，表示它语或给予者。

And would anyone really say, " To whom do you think you're talking? " instead of " Who do you think you're talking to? " Speaking of whom, it is technically the objective case for the nominative who.

真的会有人说， “你认你在和谁说话？ ” 而不“你认你在和谁说话？ ”说到whom， 从技术讲， 这格who的客观情况。