Russell started his own 'movement' (religion/cult) just like all the many, many Adventist end day movements at the time (1). I just cannot see his sincerity since he copied so many phrases they used like "present truth", "new light", "opposers", "meat in due season", "Babylon the Great", "this generation", "faithful class", "the truth", "pioneer work" and to my knowledge did not give credit to the originators (2). Is that sincere? These buzz words and phrases were in use by the Adventists or Millerites since the 1840s, and Russell copied them. Also, a sincere person searching the scriptures would have many other sincere people helping him to see why and how his 'movement' was full of heresy. He may have been sincere, but stubborn as hell, and enjoying his adoring fans, which led to evil culty actions. Here is a link to publications in PDF exposing Russellism in his day: http://www.watchtower.exposed/c-t-russell-exposed-jehovahs-witnesses-foundation/
1. The many end-time Advent magazines set to music (don't blame me, WW3 :) from Bridget fromAZ youtube channel:
https://www.youtube.com/watch?v=wWVeAhNzPcA
2. Phraseology and buzzwords from Adventist/Russell parallels. this is part 3 of 7
https://www.youtube.com/watch?v=9gTuQY5-Ya4
Then a year before his death in 1915 he was accused of kidnapping a girl with money into his cult. I cannot believe again that a nice sincere man turned into someone who allowed this to happen. People become famous with adoring fans all the time and do not turn into cult leaders that kidnap girls with money, right? There has to be a tendency (of narcissism or whatever) there from before the fame. Sure it wasn't as culty as now, but for a big newspaper to say it? That says something. Here's Bridget's video on that story in the Chicago Daily Tribune.
https://www.youtube.com/watch?v=WRbkKbQOSkE
Russell lost control of his life with all the death in his family of origin. I personally think at this moment, that he was trying to get some control of others, but I may change my mind in the future.