I like that this piece makes clear how conscious choices of which data to present (and which not to present) can make an argument more convincing without actually lying. I don't like that it makes accusations about a particular person doing so without the courtesy of linking to the person being accused. If your argument is strong, it's usually better to let the reader judge for themselves whether your accusation is accurate. Failing to do so can undermine an otherwise strong argument.

I'm not familiar with Goddard/Heller. Searching for Tony Heller, I find https://realclimatescience.com. It includes a lot of graphs very similar to the ones Tamino dissects. The ones I saw were going day by day, looking at average temperatures for that day over the last 100 years. It's good to know that the start date might have been cherry picked to make the graph look better, and that this is based on raw unadjusted data, but it doesn't seem inherently unfair to use a particular day rather than the average for the entire year.

Is there a better "smoking gun" where he makes the more grandiose claims that Tamino accuses him of doing? Maybe, but without a direct link I wasn't able to find it. And in the absence of better evidence, as long as the graph is clearly labelled "Summer Average Maximum Temperature", I have to say that it seems unlikely that he's actually guilty of "claiming to show that temperature in the U.S. has been declining", and more likely that he is making the more direct claim that summer highs have not been increasing. Which given recent newspaper headlines, I do find to be an interesting counterpoint.

Searching for Steven Goddard, I find this: https://stevengoddard.wordpress.com/who-is-steven-goddard/. I like that he clearly links his pen name to his real identity, and makes clear his scientific and environmental background, and admits that he is not actually a climate scientist. Does "Tamino" have a similar page? Who is he, and what is his background? It felt odd for one pseudonymous author to be calling attention to the fact that someone else was using a pseudonym. At this point, based on a tiny amount of research, I feel a little more comfortable with Heller/Goddard than with Tamino.