why it's defamation when i'm simply giving out fact.
It is often very hard for most people to write “pure” fact. They almost always want to embellish a bit as statements of fact rarely capture the attention or interest of a reader. And it will be these embellishments (generalizations, opinions) that open up text or speech to claims of defamation.
In addition, and as doucar pointed out, you are inserting yourself into the business relationships of others. If this interference causes harm (cancelled contracts, loss of sales), you could be sued.
Is a suit likely? Ordinarily I would say “no” but these are not ordinary times.
People seem to be suing others with greater frequency over even minor disputes, and defamation claims seem to be a sort of go-to legal action of late.