[0]: https://iphone.appleinsider.com/articles/18/10/06/bh-is-set-...
[1]: https://www.courant.com/politics/hc-pol-online-sales-tax-201...
2. In the country where I currently live, if I order something from another country I am charged the tax on import plus a substantial processing fee that's usually much larger than the tax. I miss the US system in comparison...
They don't charge them because they can get away with (or believe it is legal to) not charge sales tax for customers not in the state or area from which they operate.
If it makes one feel better to do it, by all means do it. Among the list of egregious tax offenses that exist, this is likely pretty low on the IRS list to audit people.