not to mention the fact that if you artificially increase the price of labor the demand for labor will fall
But if your Sales revenue is increasing, then that would indicate increased demand,
Not necessarily, it could also indicate an increase in per unit price (revenue = qty * price), but if you increase prices the law of demand dictates that all else being equal demand will decrease, therefore in order to be able to increase prices without decreasing demand some other non price determinate (e.g. you start producing a product with new features that are in higher demand) would have to change and cause a rightward shift of the demand curve.
which would call for more labor in order to fill the supply.
Nope, more labor would only be called for if the marginal benefit of additional production exceeds the marginal cost of additional production.
When people get wage increases, do you think they don't spend more?
Doesn't matter, when you impose a binding price floor (a price above the market equilibrium price) you WILL incur dead weight loss (foregone economic surplus) which is just another way of saying you're not producing as much wealth as you would otherwise. The only way to avoid that situation for the topic under discussion (labor) is if the productivity of labor increases which provides the impetus for higher wages without increasing the price of output, because your variable cost of input (labor in this case) is spread over more units over the same fixed period of time (making each unit cheaper to produce)... up to a point (marginal diminishing returns).
Explain to me then how cutting taxes results in increased spending, yet raising wages doesn't?
It's not "increased spending" it's increased
economic activity (transactions or
trade), trade creates wealth on both sides of the transaction, therefore the more trade the more wealth created (economic surplus (wealth) = consumer surplus + producer surplus), lower taxes increase economic activity because taxes increase prices (for both sellers and buyers) thus both demand and supply are reduced.