I doubt it was an infinite ban. Assuming the value is stored as seconds in a 32-bit unsigned integer, it looks like this was meant to be a 2 hour ban, but the sign got flipped. Because of the way negative numbers are stored in binary (Two's Complement, if you want to look it up), their unsigned representations tend to be absurdly big for most everyday negative numbers (which are typically less than 4 billion).
In a bit more detail: 2 hours = 120 minutes = 7200 seconds, and -7200 in an unsigned 32-bit value becomes 4,294,960,096 seconds, or 71582668 minutes and 16 seconds. Not quite the value above, but the screenshot could have easily been taken 5 minutes after the ban was first put in.