Freedom of speech and conditionality
This freedom may reasonably be conditional on some things e.g. public safety - so you can't shout "fire" in a crowed theatre, or the rights of those rich enough to defend their reputation if you libel those who can afford to sue you and can prove that what you said was false. But once it's made conditional on copyright owners finding your speech convenient to their business interests, then it isn't freedom of speech at all.
Also TPB don't host trackers and they haven't for about 2 years. Trackers are not needed anymore, so long as peers share addresses of other peers with each other as they now do.
The innocence or otherwise of an indexing service as perceived by copyright owners is besides the point, the question is whether the business interests of copyright owners justifies suppressing freedom of speech in saying where some machines happen to be sharing what.