Great Britain's Lutalo Muhammad won the -87kg European Championship title in Manchester earlier this year and was nominated by GB Taekwondo ahead of Aaron Cook for the -80kg division Team GB berth for the London Olympics
"It's tremendously disturbing," said GB performance director Gary Hall.
"Fans of Aaron are turning against Lutalo which is absolutely unjust."
Cook v Muhammad
Head to head wins
European Championship titles
2012 US Open
Did not enter
2012 German Open
2012 Dutch Open
Hall says, having spoken with Lutalo's father, Wayne, some of the mail is "verging on the line of abuse" and they are considering whether any legal action needs to be taken against these people.
"They [Muhammad and Cook] both entered the race together and it's unfair how it's been portrayed," Hall told BBC Sport.
"No-one took any recognition of the performances Lutalo has displayed, and the fact he has beaten Aaron and vica-versa and it's a fair competitive challenge that's been great to see for GB Taekwondo."
Last week, Hall said
has been conducted against Cook, and their decision to overlook him for Olympic selection had nothing to do with any lingering resentment towards the fighter for
quitting the GB programme
GB's performance director did, however, reveal the
of Cook from previous Olympic and Paralympic champions Sir Matthew Pinsent and Baroness Tanni Grey-Thompson had not helped the situation.
"How this story got so one-sided, I just think it's potentially the influence of the media machine behind Aaron," he said.
The 29-year-old from Doncaster says she has been impressed by the attitude Muhammad has shown in training.
"Lutalo's flying in training and almost seems like there's nothing wrong," Stevenson told BBC Sport.
"I can't speak for Aaron but Lutalo seems to be doing really well and we're all trying to stay really positive, focus on training and keep going."
Stevenson defends Taekwondo selection
World Championship bronze medallist
who won a tense battle with European champion Michael Harvey for the 68kg Olympic berth, says he has sympathy for both Cook and Muhammad.
"I do feel sorry for them both and I just hope that it gets sorted out as quickly as possible now so either one can focus on the Games," said Stamper, who also branded those sending hate mail to Muhammad as "idiots".
"It's not his [Muhammad's] fault, he's been in the academy for six months and he's done better than anyone I've seen.
"He doesn't deserve any bad press at all, he's done his job - if someone's going to give him an Olympic place he isn't going to turn it down. He's going to train as hard as he can for it."
GB Taekwondo, who officially
named three athletes for London 2012
last week, will meet on Wednesday morning, in the presence of a BOA representative, to consider the remaining 80kg division.
The BOA have insisted all members of the selection panel must vote for either Cook or Muhammad, after some members abstained in the previous selection meeting.
The sport aims to nominate an athlete by Wednesday afternoon and are hoping the BOA's Olympic Qualification Standards (OQS) panel will ratify this choice by Friday at the latest.
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