Give the specific example. I haven't heard of them trying to get someone's private tax records.
They certainly do attack rights for political gain, all the time.
Just last year they refused to meet with or vote on Obama's supreme court nominee. It is obama's right as president to nominate and it was their jobs to at least vote.
Instead they stalled for 300 days, refused to do their jobs, snubbed obama's right to nominate judges, and effective stole the lifelong appointment.
They also actively attack the voting rights of citizens for political gain every election cycle. Don't be naive.