"Sometimes people say things on the field that they might regret".
The fast-bowler was involved in a long-running verbal battle with Root throughout the day as the England man continued to frustrate his opponents.
Gabriel was given an on-field warning by the umpires about using abusive language.
Root was repeatedly asked to reveal what Gabriel said on the field but declined each time.
"It's Test cricket. He's an emotional guy trying to do everything he can to win a Test match".
"You can look at it like that but you can look at some of the dismissals I've had in there too", he told a BBC podcast.
Root enjoyed a fine day at the crease, scoring a 16th Test century and finishing 111 not out as England built a lead of 448 runs.
While it is unclear as to what exactly was said by Gabriel, the stump mics caught an interaction between the fast bowler and the England captain, which ended with Root saying: "There is nothing wrong in being gay". "If you feel form is a numbers game, then I have had a lean run but I've got a good approach to batting and it's stood me in good stead until now". The charge, which was laid by match umpires, will now be dealt with by Match Referee Jeff Crowe.
Wood wasn't done there though, as he returned to close the home team's innings on 154 runs from just 47.2 overs as the West Indies suffered a cataclysmic collapse to see them trail by a mammoth 123 runs going into the second innings.
The former cricketer Nasser Hussain, who captained England from 1999 to 2003, said Root's response was more important than his team winning the match.
Root has been praised by Stonewall, a leading United Kingdom equality charity, for challenging West Indies bowler Shannon Gabriel during the third Test in St Lucia.
Last month, Pakistan's captain Sarfraz Ahmed landed in trouble after a seemingly racist comment he made to South Africa's Andile Phehlukwayo was caught on the broadcast stump mics and discussed by the commentators.