"I personally can't speak about the incident. I'm not condoning what he has done in any way and if has to miss the Six Nations then Dylan has to take the sentence on the chin and move on," Reid said.
"But it must be remembered that Eddie [Jones] and the selectors obviously have seen some great leadership qualities in him. The captain is the man you trust - they convey the coaches' messages and team plan on the field.
"England have been playing very strongly recently and this is a reflection of Dylan's captaincy. The team would certainly be missing a central cog in the team if he wasn't there."
The entry point suspension for striking an opponent with the arm is two weeks but with Hartley's disciplinary record - banned for a total of 54 weeks for a combination of gouging, head-butting, biting, abusing a referee and punching - he could face a far lengthier ban.
Reid said Hartley still needed to smooth out some "rough edges"but added refereeing in the modern game had become "too harsh"on players.
"If you look at it on paper it doesn't read very well for Hartley in some respects but aggression is part of his game," said Reid. "Dylan is a confrontational sort of player- but you have to ask yourself if he wasn't that way would he be as successful?
"Perhaps Dylan needs to take a pause and ask himself is aggression costing him? I personally think he may need to smooth the edges off his game a little but very rarely do you want to take aggression out when playing.
"He is an intelligent player and this is simply how he plays. This is a contact sport - aggression is part of the game. I feel refereeing has become too harsh in modern times."
Any hope Hartley had of being named captain for next year's Lions tour to New Zealand now appears slim.
But Reid insisted if the Lions wanted to stand "any chance of winning"they would need a player such as Hartley at the helm.
"For the Lions to do well in New Zealand they will have to play an aggressive game," Reid said. "They could do very well with Hartley at the helm. It will be a hard tour and they will need hard men to stand up and make themselves accountable.
"I've followed Dylan's career closely and have a lot of respect for him. I have nothing but praise for the player."
European Professional Club Rugby (EPCR), who organise the European Champions Cup, confirmed on Saturday that Hartley's disciplinary hearing will take place within the next five days.
- Additional reporting by Sam Peters
