As far as I've read, Jainism seems to be the least blemished religion, is this true?

sense?

I haven't heard anything particularly negative about Jainism, Buddhism, Shinto, or Taoism.

It might be true, but, there again, it is also a relatively small religion. So, it doesn't really have the numbers to make any real impact--good or bad--on the world.

SB 5.6.9 The Activities of Lord Rsabhadeva
Sukadeva Gosvami continued speaking to Maharaja Pariksit: My dear King, the King of Konka, Venka and Kutaka whose name was Arhat, heard of the activities of Rsabhadeva and, imitating Rsabhadeva's principles, introduced a new system of religion. Taking advantage of Kali-yuga, the age of sinful activity, King Arhat, being bewildered, gave up the Vedic principles, which are free from risk, and concocted a new system of religion opposed to the Vedas. That was the beginning of the Jain dharma. Many other so-called religions followed this atheistic system.

PURPORT
When Lord Sri Krsna was present on this planet, a person named Paundraka imitated the four-handed Narayana and declared himself the Supreme Personality of Godhead. He desired to compete with Krsna. Similarly, during the time of Lord Rsabhadeva, the King of Konka and Venka acted like a paramahamsa and imitated Lord Rsabhadeva. He introduced a system of religion and took advantage of the fallen condition of the people in this age of Kali. It is said in Vedic literatures that people in this age will be more inclined to accept anyone as the Supreme Lord and accept any religious system opposed to Vedic principles. The people in this age are described as mandah sumanda-matayah. Generally they have no spiritual culture, and therefore they are very fallen. Due to this, they will accept any religious system. Due to their misfortune, they forget the Vedic principles. Following non-Vedic principles in this age, they think themselves the Supreme Lord and thus spread the cult of atheism all over the world.