In many parts of Europe - e.g., in Germany and in the UK - the purchase of many common "dangerous" reagents is regulated and illegal without a license that isn't available to hobbyists. The government takes the view that it's simply not a legitimate hobby.
In the US, the situation is better, but some essential chemicals are unobtainable due to DEA legislation (iodine, phosphorous). Many others are subject to DHS and DEA monitoring (including KYC mandates) and a patchwork of state laws that prompted most reagent manufacturers to stop shipping to non-commercial customers altogether - and in recent years, also caused them to also crack down on resellers (requiring every reseller to attest that they will not re-ship to civilians). In the past five years or so, eBay also had major crackdowns, banning everything from sulfuric acid to potassium iodide. So did Amazon.
And that's before we get into raids on YouTube chemists, etc. Heck, Texas prohibited people from buying or owning laboratory glassware until recently. Wikipedia has a good summary.
The internet made chemistry easier for a while by facilitating trade, but that era is coming to a halt.