Main reason why most people prefer tumbling is privacy and not because of getting blacklisted for using gambling sites which in case only Coinbase does this kind of behavior.
In your article you mentioned about coinjoin which is not effective anymore due to the fact that you will be traced back to your main address by reverse engineering process.
Nowadays what people prefer is to mix coins via already available trusted tumbling services like Bitmixer. They have a large reserve of coins and you will be able to tumble your tainted coins easily.
I would say it's not a bad idea to always mix coins before putting your coins into a centralized service. There are lot of mixers but as far as I know one of the best if not the best mixer possible is Helix, ideally you access it with tor through their onion hidden service. You enable random transactions and delay and then you get untraceable bitcoins back. Use those to gamble and pay for stuff.
Of course with shit like Coinbase you never know, they may find out that the coins you got back from the mixer were used by some criminal activity and now you are fucked... but as far as I know Helix gives you clean coins that got recently mined so that wouldn't be a risk.
Anyway, just avoid services like Coinbase with an history of trying to trace people's bitcoins records which is stupid since we don't have control over were the bitcoins we have came from.