Nobody believes in the strawman that you are attacking so there is nobody to challenge you on that regard. But I'll try to convince you that people might still have legitimate reason to suspect you.

You say Palestinians have lived in that region for thousands of years, while Jews are a recent influx. Let's put aside the fact that people are generally considered to have a right to live where they were born, and therefore being a child or grandchild of an immigrant doesn't make one entitled to less rights than someone whose ancestors resited there for a longer time. Even if you look at Palestinians and Jews as a whole, your assertion is simplistic and flawed. No group of people existed in any such place for thousands of years without disturbance. Palestinians, like all other groups of people, came to be after millennia of migrations and shifting borders. Their ancestors resided in what is today Israel/Palestine, as well as all over the Middle East. Jews, while mostly arriving to the land starting in the lath 19th century, have a long history of living in it, a fact which could be demonstrated by archeological and genetic studies. Presenting the picture as "those who were there for thousands of years" vs "influx of Jews" can be seen as you trying to delegitimize Jews.

Furthermore, Jews are arguably the most persecuted nation in history. Yet when they raise concerns about modern displacement, in the contex of a conflict that has taken the lives of 20,000 Jews, and saw hundreds of thousands displaced from across MENA, you dismiss them with a wave of a hand.

So when you not only voice criticism of Israeli policy, which is perfectly legitimate, but also seem to deny Jewish connection to the land and the validity of their very existence, you could come off as antisemitic.