What did he mean by this?

Have you seen how Gaelic is spelled versus how it is pronounced?

...

for serious now: I don't know shit about Gaelic besides the memes, is its spelling inconsitent or just weird to other euros?

All words are made up or evolved from other words someone else made up.
The word was used in English as early as 1902 by Richard Henry Pratt. Like many words it has no clear past however, and this is only the earliest use in English recorded by Oxford. The word "racialist" was also used around this time period. Equivalent words were also around in other languages like French before this time (cnrtl.fr/etymologie/raciste). It should go without saying that the topic of racial liberation was around before Trotsky or Pratt were ever born, regardless of the present terminology.
He used an equivalent term in "The History of the Russian Revolution", which was published in 1930 and translated into English in 1932. I have no idea where "1927" comes from. Trotsky did not translate this book into English, someone else did. If this was where the word "racist" in English came from, it would have been coined by the translator, Max Eastman, not Trotsky. It can be read in .pdf form here: marxists.org/archive/trotsky/1930/hrr/
Is that really how it feels to be described the way you are? Do you feel bullied?
The word was used by Richard Henry Pratt twenty-five years earlier to attack racial segregation. Is the implication here that opposition to racial segregation was a communist idea?
If you had any balls at all you would accept the label and describe yourself as a racist. Then the ones who would "shut down" are the people who think calling you a racist in itself is enough to end the argument. Are you maybe scared of the idea of racism, but like the racist ideas themselves? If more of the closet racists were open about their views, perhaps some of those anti-racists would reconsider how sound their arguments against you are, and come up with better ones. Can we please be honest about our ideas and quit this wishy-washy bullshit?

Anyone else grateful to comrade Trotsky for arming the revolutionary movement with this weapon?

There's nothing quite as satisfying as watching a reactionary squirm as you call them "racist" knowing fully well they are.

Thank you based Trotsky.

en.wikipedia.org/wiki/Racism#Etymology.2C_definition_and_usage

I was going to post about this, righties seem to hate being called racist but when they're on a safe space they will ambrace the world and celebrate their racism.

Scottish Gaelic and Irish have fairly regular orthographies, just idiosyncratic

"Racist" is a loan word from French. It wasn't invented by Lenin.

Marx and Engels described the various ethnicities of volker-ruinen whom they branded as counter-revolutionary when they wouldn't allow the communist new men to dictate their whole life to them from cradle to grave.