If they didn’t, you’d probably see a backlash just like we saw with the amnesty bill.
The populace, equally generally, do not understand tax arithmetic (unsurprisingly, since it's so deliberately obscure in many cases). Case in point is the famous ''23% figure that the 'fair' taxers throw about. For over 200 years of the Republic, sales taxes have been computed at retail as what you lot call an 'exclusive' tax.
Now, you lot want to spout an 'inclusive' rate, the better to deceive by using a lower figure, instead of the accurate (and traditionally calculated) 29.87% rate. You are attempting, effectively, to substitute the calculation of 'markup' (i.e. based on final sales price) for the calculation of 'profit'' (i.e. based on cost of goods) .
And this is completely dishonest. As are the 'fair' taxers.