The reason they say no to begin with is because you are not pitching in a vacuum, you are pitching together with another 1,000 or so companies in a year, 900 of those will get 'no' right off the bat, 100 will get a meeting (or two) dedicated to reviewing their proposition in more detail, 10 of those will enter due diligence (at substantial risk to the VC in case the deal does not go through) and maybe 8 out of those 10 will get funded.
The amount of time wasted on worthless pitches by people that don't stand a chance of getting funded is very large, and no amount of feeling that you are entitled to funding is going to get you funded unless you manage to convince the other side of the table that you are one of those 10, which means you need to look better than the other 990. Good luck!