OP this is classic. You are upset, you post, you get a wake up call from everyone on here, you minimise and start saying he isn't that bad. He is.
How dare he say he isn't washing up because you havent today. I would be saying well, I won't be cooking for you today as you haven't for me. And while we're at it I won't be washing your clothes as you don't do mine. Two can play at that game. Your son is playing manipulative games with you. If you let him get away with that sort of answer, you only have yourself to blame for what happens in the future.
If this was a 17yo I might answer slightly differently as there's still some growing up to do, but your DS is through Uni, he is an adult, he needs to support himself and he needs to be very grateful that his parents are letting him stay at home while he pursues a job.
Stop backtracking OP. This is just what my friend with the sons used to do when it became obvious they were treating her like shit. She was an expert at changing the subject with me when reality hit her with how her sons behaved. The thing is, her sons (probably like yours) weren't all out drug taking pissheads smashing up the house or hurling abuse at her. However, they treated her like something on their shoe, the younger son learnt from the oldest. She never stood up to them and so they were able to put her down and treat her like the lowest of the low. As long as she cooks their favourite meals and does what she's told, everything is hunky dory when they are home. They are now entitled boorish idiots because they've never been pulled up about anything at home. When I visit and they are there, it's like they are royalty deigning to pay their family a visit. I pity the poor women they end up marrying.
Wake up OP... you need to sort this.