Correct me if I am wrong @jpphotography and @for91days, but I think they do not collect any taxes right now. Their main goal is to improve the app and add some new features. I don't know how it will be in the future. Personally, I think that taxes are not a bad thing at all. (As @onealfa would say, there is no free dinner and free cheese is only for the second mouse).
The most important thing is the quality of the platform, quality of the posts (they do manual curation) and a good community. Reaching these goals takes a lot of time and effort and at the end of the day, people doing it should get somehow rewarded and the project should not be funded from their own pockets as it might not be sustainable. Actually, I really like @threespeak business model. They collect a small monthly fee. This scares spammers away. @travelfeed do it in another way. They encourage writers to write at least 250-word articles or longer.
Perspective
Another way of looking at is simply what you can get out of it as opposed to calling it a tax, perhaps. It is possible that this tax thing that we are talking about in regards to blockchain is more the cost for transactions which might be part of the reasoning Steem has RC Mana as a system for describing the units for transaction costs. So, in other words, RC is not the same as what the IRS does with fiat currencies or I mean with the dollar.
Concern
One of my concerns would be if an app was to subtract funds from my wallet, the Steem, SP, and/or SBD, daily or per transaction, that is without consent or excessively or without me being aware of it. Transactions on Steem costs RC and not SP, I think. So, if that is the case, then I think that is good to extract from RC and not from SP or from what is already in the wallet. Potentially, some people could maybe go bankrupt or that direction if an app is taking from what is already in the wallet.