Fenths are more valuable then normal resources, since they can fill in for missing resources. Most resources are tied to lands now, and not available freely to people of other countries, except through trade or gifts, (either for other resources or coins).
if people want to lend the coagulator to collect the fenths of their own crits. I'll happily lend them the coagulator. But I do feel that I should be able to trade the fenths I made from my own creatures, Just like resources which are traded for coins, I put in time and effort to train my creatures and gathering fenths.