People converting to any other religion does not create problems. I have seen guys who had recently converted to religions such as Buddhism, Judaism and even atheism. But they are normal people. Only individuals who convert to Islam create issues.
I have to agree with you on that the newly converts to Islam cause even more problems than those who were born into the religion. I don't know the kinds of zeal that they have when they convert to Islam
Unlike the people who convert to non-Islamic religions, converts to Islam are mostly from the lowest levels of the society, such as mental patients, drug addicts, criminals, delinquents.etc. That may be one of the reasons.