No, they didn't issue warnings because they didn't have to. If they did have to, they would have issued a warning, then found that no action he might take could

No, they didn't issue warnings because they didn't have to. If they did have to, they would have issued a warning, then found that no action he might take could have remedied the situation (the things in the memo that were considered harassment can't meaningfully be taken back), and then he would have been fired.