Lee had attacked the Union’s northern and southern flanks and were repelled. So Lee thought Meade had heavily fortified his flanks and left his center weak. Instead, the north barely held onto its flanks and was using the center to hold all of its reserves. The Northern defense of the southern flank is legendary: a downhill sweeping charge by the very last standing regiment at the very end of the flank saved the day. See “little round top” for more.

That said, anyone could just look at the field in the center and conclude any assault was suicide but southern chivalry was in full swing.