You are 100% correct. All these people are not Jewish. 400 years of intermarriage and they think they're as Jewish as King David. They demand a fast "halakhic return" because "conversion is an insult" that they should not have to go through. I argued with one of these "bnai anusim rabbis" once on why should they get special treatment and a fast halakich return while the son of a Jewish man and a non-Jewish woman has to go through a conversion. I could get no answer. They whine about their so called "400 years of suffering" which is ridiculous. You want 400 years of suffering, try being a Jew in Europe 400 years ago.
What they forget is the reality of the situation. When forced with conversion, a Jew must accept death rather than convert to another religion. In Spain and Portugal, the Sephardic Jews got a choice. Convert or LEAVE. Many Jews chose to leave and went to Amsterdam, Morocco, Turkey and the Balkans etc... And guess what? They are still Jewish today. They left and built vibrant Jewish communities elsewhere and lived by the Torah and are Jews now.
The rest chose to convert (a grave sin) and live in Spain and intermarry and now their non-Jewish descendants demand to be regarding as Jews without the need to convert. And it's a big farce, all these supposed "bnai anusim".
I had an interesting conversation regarding the so called "Indonesian Jews" who really are the children of intermarriage and who did a bunch of so called conversions in Indonesia, but now regard themselves as a "lost tribe who made it back after some type of years of suffering". No, they are not a lost tribe, they are a group of non-Jews whose male Jewish grandfathers intermarried with the female Indonesian natives. Even the real lost tribes have a big problem with intermarriage considering they come from the kingdom of Israel, which was carried away due to their wickedness.
Anyways, I believe there is one organization that helps Jews with aliyah, although I don't remember the name right now, but will post it when I see it.