When we say "trans men are men" and "trans women are women", we mean it unconditionally.
When somebody says "I am a man", you accept them and see them as a man, and when somebody says "I am a woman", you accept them and see them as a woman - there is nothing that they need to do, say, think, believe, etc. in order to be "accepted" as the gender they say they are.
A trans man can use she/her and still be a man, and a trans woman can use he/him and still be a woman; a trans man can be incredibly feminine as a man, and a trans woman can be incredibly masculine as a woman; no trans person has to take hormones or have surgery to be accepted as their true genders - no trans person has to do or say anything in order to accept them as their true genders.
So if you read statements like "trans men do not have male privilege", "trans men experience misogyny", "trans men are oppressed for being trans men", etc., and think that it means we don't see trans men as real men, you should ask yourself what your idea of a "real man" is, really ask yourself.
"Although brown and black bodies were designated female and male, the science promoted by the American School of Evolution regarded sex difference as a racial characteristic and argued that only white European-derived people had evolved to the point of having distinctly separate male and female brains and dispositions. According to Kyla Schuller, associate professor of race, gender, and science studies at Rutgers University, the prevailing scientific thought at the time regarded this crucial sex difference between men and women to be behind the development of rationality and reason, which to the scientists was a hallmark feature of (Western) civilisation.
Racialised people, in other words, lacked the proper differentiation between men and women required in order to be rational and, therefore, civilised. In her stunning analysis of nineteenth-century race, sex and science, The Biopolitics of Feeling, Schuller outlines the ways in which binary sex was regarded as both cause and effect of reason—which only white people had—making binary sex itself a function of race. To the leading evolutionary scientists of the era, the supremacy of Western civilisation lay firmly in ‘its ability to restrain animalistic impulses and maintain sexual differentiation of the civilized’."
-(White Tears/Brown Scars by Ruby Hamad, page 55)
When TERFs say things like "trans men experience misogyny" or "trans men don't have male privilege", they are putting trans men in the position of "cis woman." They do not see trans men as men, they see trans men as "cis women" who are oppressed as "cis women."
So when other people say the same/similar things, it can be a kneejerk reaction to assume that they are saying it while misgendering trans men as women.
White supremacist society wants you to see men as oppressors and women their oppressed property. It wants you to see white women as innocent, weak, and in need of protection by white men. White women are not white men's property to be "protected", and any kind of rhetoric that plays into this is racist and white supremacist - yes, even when it's about trans men and trans women!
"White people set the standard for humanity by which they, and only they, could succeed. And this standard meant a strict hierarchy that placed white men at the top with white women just below them, followed by men of colour, and then women of colour occupying the lowest rung. I do not mean to say here that all women of colour’s experiences are exactly the same or that there is not a discrepancy in privilege among them, only that whatever their race or ethnicity, women of colour are always considered below both white people and men of colour. White women were the beneficiaries of a status higher than that of people of colour but subordinate to white men, and it is this very status that enabled colonialism to succeed. The American School, explains Schuller, acknowledged that both thinking and feeling— sentiment—were crucial to evolution and civilisation; however, too much sentiment led to sentimentality, which could hinder objective thought. To solve this dilemma, evolutionary race scientists effectively split the civilised, aka white, body in two. To the male half went the higher intellectual faculties of reason, logic and objectivity, and to the female went excessive sentimental responses and the accompanying tendency to irrationality and impulsivity. Women would take on the role of feeling, of sympathising, of ‘letting emotions override the facts’, leaving men to carry on the important work of intellectual endeavours and empire-building. In this way, Western civilisation would be secured and stabilised."
-(White Tears/Brown Scars by Ruby Hamad, page 55)
(Although it should be noted that White Tears/Brown Scars comes from a cisnormative lens and therefore does not take the experiences of trans men into account)
But trans men are oppressed, and they are oppressed AS trans men.
TERFs do not believe this, they do not believe this to be the case, and don't believe that it's POSSIBLE.
They believe that trans men are either oppressed as "cis women", or privileged as "men", because they do not believe it is possible to be a man without being an oppressor of women, or that you can be a man without male privilege, or that trans people even are the genders they say they are in the first place.