I don't know why anyone would want to make an issue of this other than to throw out the ridiculous "coons" interpretation but the word that preceded 'effing' sounds like 'these' to me and has been reported as such by almost everyone. "These 'effing' cold" doesn't make much sense. Especially when it was probably over 60 degrees at the time. But I suppose in FL that might be considered cold.
You didn’ listen to the part that preceded the part you quoted she told Zimmerman to keep an eye on Martin not once but twice. If she had just told him twice to keep an eye on Martin, why would she then turn around and say we don’t
need to have you follow him,
It makes as much sense as Zimmerman making a racial comment to a person on the other end of the phone conversation, when he can’t tell the color of their skin. You may make an off color comment to a friend, but not to a stranger over the phone.