If Orthodox Judaism is only a few hundred years old, how come Orthodox Jews are put on such a high pedestal in Israel (and beyond)?

I recently found out that Orthodox Judaism didn’t really become a thing until the 18th century — while Judaism is almost 6,000 years old. And as a very reform basically non-practicing American Jew, I’ve always found it to be extremely hurtful and a little infuriating to be poo-poo’d and sometimes not even considered to be a “real Jew” by some people in those communities.

I had a great grandfather (never met him) who was a highly respected Orthodox rabbi in New York, both of my grandparents on my father’s side are Holocaust survivors and many people in my family were murdered by the nazis. I was sometimes singled out and picked on growing up decades ago just for being Jewish. I have family in Israel. So okay, I’m not a Jew at all to a Haredi rabbi just because I don’t observe the way they do? Really? I’m very proud of our culture, many aspects of the religion as well and the countless achievements our people have contributed to the world.

But why are Orthodox Jews, a relatively small portion of the Jewish population overall that’s only about as old as America so often considered to be the authority on who or what is truly Jewish? Why are they so special that they could avoid mandatory military service in Israel, as one example? I know this is a highly controversial thing to say but I find many aspects of Orthodox Judaism to be quite problematic and even contradictory to the ideals shared by most other modern day Jews around the globe. I don’t harbor hate for my own but I don’t feel that many Orthodox Jews have much love or respect for people like me either. An ethnic group so small and historically persecuted should have each other’s backs no matter what, no?

As someone who admittedly hasn’t delved deep into the topic, can someone explain why Orthodox Jews are held to such a high regard when it comes to determining what and who is Jewish in Israel and beyond?

Sorry if I offend anyone here it is not my intention, this has just been on my mind for a long time and I thought this would be a good place to get some answers. Thank you and shalom.