In the B2B world, at least in Europe, businesses don't count the VAT in what they pay. It is common sense that a price is displayed "+VAT" or other tax names for other countries (TVA in France, IVA in Spain etc...).

Not having the possibility of showing the pricing without VAT means a visitor will think you are basically 20-21% more expensive than what you actually are. It is a massive business-block.

To sum it up:

If my business sells something for 100€ to another business, the final price their credit card is gonna pay is 100+Tax (say 20%) = 100+20 =120€.

But they only care about the 100€ pricing as company don't pay these taxes in the end (they get them back from the state afterwards basically).