I put trust trustpilot as much value as newbie accounts in bitcointalk. Both of them van be weaponized with money, either for praising the product or FUDding the competition.
Also i didn't even find anything that would make Freebitcoin admins "greedy". And being "greedy" is just weirdest fud. Like not every company out there wouldn't want to make more profit.
Trustpilot is also a place that takes money to delete bad comments if you pay them. It has been leaked before and there were mails from the staff members that said if you paid them X amount (changes based on how many bad comments there are) then they can delete some of it, and that made the overall point you got there better.
I am sure you can abuse it to promote your business, but their entire business model is based on blackmailing companies into saying "take my money and delete bad comments", that's how they are managed. Thankfully freebitco.in doesn't need any of that, they are already one of the most visited crypto websites, so they don't need trustpilot to say anything about them.