RE: non conductive soder ?
What they are saying is that the FLUX is non conductive not the solder. Flux is a chemical that chemically cleans the metal when heated and allows the moten solder flow and get a good bond to the base metal. What you have there is a Rosin core solder, good for electrical work and other things. There is another type of solder that is acid core, stay away from that stuff unless you want your soldered connections to get eaten up in due time.