Ah, so today we have full conspiracy theorist jopo.
1)
From stolen informal emails you take "It would be good to remove at least part of the 1940's blip. But we are still left with "why the blip"",
and you leap to the conclusion this is "evidence" they altered data inappropriately. That's a nonsense. It's two scientists discussing an anomalous spike in the ocean data that appears to have no explanation and that measurement changes were likely a factor in. And they are discussing how it is inconsistent with the size of the land temperature data spike, so is anomolous compared to all other spikes.
The resulting adjustments are the ones you showed - repeated below. Sea temperatures are lifted - reducing the warming, because of the issue with sea bucket temperature measurements and the change in the way those measurements were carried out.
The adjustments did exactly the opposite of what you are claiming. They cooled the amount of warming measurements show. And the correction reduced the blip bringing into line with expectations and normal correlation compared to land data.
2)
Hide the decline, jeez, it was a splicing exercise to bring two datasets together where historic tree ring paleo data merged with modern temperature record data. The findings of these stolen emails were subject to a number of reviews and the science was found to be robust. The reason to "hide" some data is because it is invalid. More recent tree ring data does not show correct growth rates relative to temperature, as discussed here. https://www.skepticalscience.com/Tree-ring-proxies-divergence-problem.htm
It was an issue well discussed in peer reviewed science since 1990 and correctly reflected in how the data was handled.
I could go on, but I've got better things to do than chase after someone wearing a tin foil hat and ignorantly copy pasting every climate conspiracy theory there is.
