The biggest driver for PED rules isn't to stop players from getting an in-game advantage. You can still use supplements like protein, vitamins, creatine. You can eat healthier food. You can take approved medication. These are all very literally performance enhancing substances. None of these are banned.
The goal is to keep players safe from themselves. The PEDs on the list are banned because they're effective and dangerous when not used in a controlled manner. The fear is that by allowing athletes to use these substances, you'll get a situation where someone doesn't know when to stop, and will either overdose or do serious harm to their health in the long term.
By allowing these PEDs you also create this new metagame in elite sports, where success it's not just tied into training with the best coaches/facilities or having the best equipment, but also having the best PEDs. Not that this doesn't already exist, but at least there is risk associated to it. Legalise it, and you open up a dangerous world where people could kill themselves trying to get an edge over the competition, and where breaking into professional sports by definition requires you to dabble in this world. Again, not that this doesn't already exist, and some sports are worse than others, but that is why we have the worldwide effort here to stop it.
Cricket, by it's nature, isn't a sport the benefits hugely from abusing PEDs, and so that's why we aren't as exposed to this as other sports are. But with heavier workloads, especially in the franchise T20 world, and more money to be earned than ever before, it's only natural that young athletes are going to be looking for that extra few percent performance increase that these drugs can give. So it's a good thing that this is being taken as a serious matter. Nip it in the bud, don't wait for it to become a real problem.