This is not a criticism of you, you do not know what you're talking about. What you have said is generally the attitude that I would expect from someone with little knowledge of racing in general. People like to bet on the Grand National in particular as it is a spectacle, a tradition that doesn't warrant its hype, but they do not like the consequences of such a race. Quite simply if you have a passion for the welfare of the racehorses not only should you turn your TV off, you should not be betting on the race for your own entertainment. For everyone else it is about the only race that still gets advertised and talked about in the mainstream media, so sure, jump on that hype train.
Now in fairness it is not even the race that is the problem, it is the course. Since the changes there have been less deaths in that particular race (but I am pretty sure a number of the runners have been destroyed as a consequence the race, its just not widely reported or talked about), but still just as many deaths if not more, in the other races using the Grand National Course. I would think in the future that if they are to take their head out of their arses and forget about the tradition, they should look to severely reduce the amount of runners in all of the races over that course.
Personally I just dislike the race as it is a mugs race. You're getting terrible value on basically anything you bet on. Its not a race for horse racing enthusiasts.