* They have decided to prioritise getting Atlantis ready rather than being sidetracked by a PoW update to defeat the ASICs right now. Whether you agree or not with this policy the considered opinion of the developers is that this is the best policy for the longer term.
* The code is in alpha state and they don't want to release the source code until the project is more complete and aligned with its originally stated goals. Whether you agree or not it is a considered opinion and policy, and yes, you have to trust the developers for now that they really will release the code as promised. (They know it would be insane not to - it would be the death knell of the coin and all their efforts would have been wasted.)
* They do not want to register the coin on any more exchanges until it is more ready for prime-time. Again, you may not agree, but it is a considered opinion and basically has become official policy.
Come back again in 1-2 months. If the developers have seen through on their promises (Atlantis released with features as already announced; source code released; ASICs defeated - among much else achieved by Atlantis; Dero registered on another and better exchange or at least in the pipeline by then) on the timescale promised, then you know what? It really means a lot. It enables people to put much more faith in the developers and the coin. Price will rise. It will be taken more seriously. The coin will be much stronger. And if you support the coin, at that point you will be much happier, too.
Consider the following 1-2 months a test. The team have put themselves on the line. There is no point trying to change the opinions/settled policy of the developers at this point. Just sit back and wait to see how it all pans out. If it pans out according to plan, you will be in an excellent position to still be one of the early adopters of a great coin with a much greater degree of confidence in its ultimate success. If it doesn't, then the weaknesses of Dero and its team will have been exposed and you can move on, at relatively little cost to you. Either way, you will find out, and benefit.
EDIT. And consider what has already been achieved. Recoding the blockchain into another language was no small matter, and on top of that transitioning the mining pools and wallets to the new version of the blockchain has gone almost without hiccups - and with a big increase in hashing power to boot, and three attacks to the network fended off successfully. And also think to yourself: why have they bothered to recode the entire thing into a new language? Reflect on that, and then realise that the developers mean what they say when they say they are looking at the long-term success of the coin. This is no ordinary Cryptonight fork.
Good questions. Q3 2018 is crucial time for this coin.