If I did that, then I'd have to hold all donated funds forever just in case the donator scammed someone, and the donations would be useless. The forum is not an insurance company.
You think its plausible all forum donations, or even a majority are done with stolen funds? And if so, you wouldnt mind crowning the thieves "VIP" and keeping the money? As for holding the funds, you've been doing that anyway. You've been given ~6500 BTC, enough to buy a decent sized software firm, but after all these years we dont even have a search function that actually works. Why dont you do whats right for once, not because you have to, but because you can ?