Is any of this true?
I'd recommend ignoring kano, since so much of what he says is a lie.
Other pools (like eligius) black list addresses coz they think gambling sites are a ddos on bitcoin
Eligius is one of many responsible miners which have improved script matching to filter out spam/DDoS attacks against the Bitcoin blockchain.
Blacklisting is "punishing or boycotting a list of persons who are disapproved of". Eligius does not do that.
The spam filtering only matches the known spam scripts and not the person(s) responsible for the spam.
Bitcoin Core has similar, but less updated, pattern matching enabled by default for a long time - since Satoshi's maintainership (0.3.x).
Since the advanced patterns mostly match by coincidence and can be easily changed by spammers on a whim, these patterns are not appropriate for a reference codebase, which is the primary goal of the Bitcoin Core project.
Miners are
expected to set their own policies anyway, and not rely on the defaults.
Also note the patterns only match spam, and are not in any way related to gambling.
There are many gambling websites which do not perform attacks on Bitcoin.
and add hidden rules about what transactions they will ignore ...
This one is a simple lie.
The codebase used for Eligius's policy is in my public git repository, and documented on the website.
and had agreements with companies like MtGox to accept their transaction through a special interface ...
Yes, at one point Eligius had an interface for MtGox to prioritise their transactions in exchange for hosting and a link at the bottom of MtGox's website.
(and send their miners blocks with empty transactions to speed up their slow pool software ...)
This just shows his ignorance.
Empty blocks minimise your stale shares.
Eligius (and probably most cluefully operated pools) send them as soon as a new block is found, so that you can begin mining immediately.
This is also followed up with an updated block full of transactions that miners can begin working on as soon as they receive it.
If your internet connection is 10 Gbps, the empty block might waste a few bytes of bandwidth and you'll get the full block immediately to begin working on.
If your internet connection isn't so fast, you'll begin working on the empty block, then transition to the full one as soon as you finish receiving it.
Of course, this is assuming you're using optimised software like BFGMiner. It's quite possible kano's cgminer is buggy in this regard and will mine empty blocks even after it receives the full one - I don't know, not my concern.
who knows what they will black list next ...
I guess he likes to use FUD to promote his pools, since he can't find any logical/real benefit...