I don't know if bitter is the exact description, but I thought it was dumb to keep Free over Parnell, especially considering that Free had ankle surgery in both Jan 2014 and Jan 2015 and Free is 31. There was minimal if any drop-off from Free to Parnell in 2014 which is amazing considering that Free came into the season with about 80 starts and Parnell had 1. The probability is that Parnell will only be better next year while at the very best Free will be the same as he has been and more likely will decline.
There were actual NFL professionals that believed that Parnell was a good player. Jax had the option to offer a contract to either Parnell or the Packer's starting RT Bulaga, and they chose Parnell. Parnell got 13M guaranteed to only 8M for Bulaga.