• They collect sales tax now.
In 2018 in the case South Dakota v. Wayfair the Supreme Court overturned the 1992 case (Quill v. North Dakota) that had ruled that states could not force merchants with no physical presence in the state to collect sales tax on mail order sales to state residents. If a company is doing enough online business with customers in a state, that state can now force the merchant to collect tax.
If you get a B&H store credit card [1] and use it for your B&H orders (which is all you can use it for since it only works at B&H) they give you an instant reward at checkout equal to whatever your sales tax was. In effect then, if you get and use that card there B&H pays your sales tax transparently for you.
• With two exception for the most part online shoppers can ignore the Jewish holiday closings. The website still works so you can still shop. I think you can even still place items in your cart and maybe submit the order. Orders just are not processed until the holiday ends.
Most of the holidays are just a day, so if you hit one of those its not really a big delay.
The two exceptions are Passover and Sukkot. Those are each one week long. Passover is in March or April, and Sukkot is in September or October. That's long enough to be irritating.
[1] https://www.bhphotovideo.com/credit-cards