How do you hide EVERYWHERE [ "date" ago ] ?
You want something custom. There is no option to hide all dates, so I think you should ask for pro support to let them write custom CSS code for each date section. You may consider to pay for pro support or you can wait for our community members, they may help you to do that with custom CSS code. The main support staff may help in a few cases but not with multiple custom changes.
Is the Extended wpForo plugin support a lifetime support? Or 1 year?