Earlier quoted context omitted.
Judaism (to take an example) was a contemporary of those religions too - it hasn't changed an awful lot over the intervening time span. You seem to shrug off "what people believed 2,500 years ago" as, perhaps, silly or illogical and then chasten someone for doing the same to current religion :)
2,500 years ago, Jews were slaughtering goats and offering them as burnt offerings on altars in order to absolve themselves of sin. Modern Judaism is distinctly different than what was practiced two millenia ago.
The reason it's not practiced today is 'just' because the decree also states that you have to perform the sacrifice at the great temple on temple mount. That poses a technical problem, since: 1. The temple was destroyed 2k years back, and there's a pretty famous mosque standing in its place. 2. Religious jews have to do a special kind of purification in order to even be on temple mount, and this purification is impossible at the moment, again for weird technical reasons (they need a red cow, don't ask).
BUT, if there was a temple, and there was a purification rite, religious jews would, in all likelihood, be happily burning offerings 3 times each year.
In short, not as different as you may think.