Why is it that I can't thank (or groan) the posts of some users?

[Sirthinksalot]

Just a general question, posters such as Legion and SmarterthanYou do not seem to have the option to thank or groan posts. Why is this?

 

[Billy the Great Khan]

Those users specifically asked for that feature to be turned off for them.

 

[Sirthinksalot]

Those users specifically asked for that feature to be turned off for them.

Thank you for the info.