Obama wasn't the president in 2005. He was the newly elected junior senator from Illinois. Though he wasn't the president or a Texas senator, Obama did visit with evacuees at the Astrodome, along with former president Bush (41) and former president, Clinton.
I wish I could say I haven't seen a lot of this, but it's everywhere. God help us.
Chelsea Manning wasn't pardoned. Manning pleaded guilty and served over 6 years in prison before her sentence was commuted. Manning's felony criminal record stands, along with the attendant consequences of a felony criminal record.
The considerations behind pardons and sentence commutations tend to be idiosyncratic, so direct comparisons have limitations, but a better comparison with Arpaio would be whether one approved of Bill Clinton's pardon of Marc Rich.