He's not doing a pump and dump. (He does make jokes.) There are bots that buy any coin mentioned by his account, because daytraders realized he's a celebrity and that most people don't read the white papers and listen to anyone famous, so it just looks like he is pumping and dumping. But unless he is using a bot himself, the price adjusts back to normal within too short a time for him to profit from it.

What he seems to be doing is actually quite rational if you have significant funds: hedging. Any coin that is borderline decent he buys. He often tells others about it.

Caution is needed here! What's rational for sufficiently large investors is not always rational for everybody else. Quality of altcoins is not enough predict which shall win market share. And it's easier to deal with many small losses and a few large gains than the same average comprising many small gains and a few large losses. He almost certainly knows that. So like most others, he just buys, and recommends, any altcoins that he thinks are better than borderline acceptable.

It's not necessarily something you should do if you lack the funds to properly hedge, because you can lose quite a bit of money, but unlikely that he or any fund would lose if he does all he recommends, it seems to me.

This is what large hedge funds do to get returns with (relatively) lower risk. I'm not sure most people realize that. (The foolish interviewer who talked with Jim Simons at a TED conference asked him what research he does to get returns with lower risk. Simons told him that he hires good scientists to do creative research. The interviewer led and Simons did not correct him; that is not sufficient.)

Nobody in finance bothers with whether individual investments have done well or not. That is something that should be more widely known; they know that quality of investments is never entirely sufficient for investments to do well. They look always at some basket.

Unfortunately, if you lack resources to get a basket with a lot of each, you either do not profit when one or two go way up, or are gambling and lose quite a lot. The risk for them is higher than they think and maybe they are better off not to invest, even if they miss out.

The misunderstanding about risk seems to me to be behind all the conversations about pumps and dumps. For anybody who lacks resources, almost any recommendation is far riskier than for somebody with greater resources. But most people don't realize this. Risk is defined for all investments one makes together, and is further subjective so far as it depends on resources one has, for the "knock out" probability during a decline in value is higher for those with fewer resources. There is no such thing as an investment that is a good investment for everybody, because whether it is good or not is investor context sensitive.

No financial advice exists; only general theory, which is often true but not advice any more than knowing the principles of quantum mechanics helps predict where the football goes in a game. All recommendations are just summaries of what one investor did or wants to do, opinion pure.

There are obviously bad investments; but there are not universally good ones, and that is (perhaps unfortunately) yet another reason why the rich get richer and the poor generally do not.

[...Hmmm. I seem to have written another long comment. I should turn it into a post...]