Whether intentionally or not (it seriously doesn't matter), the hair, the deep black color, and the lips of the emote are, at the very least, conspicuously similar to blackface.

Blackface is considered extremely offensive in the US and most other place (though some cultures consider it less taboo). Still, as is evidenced every Halloween by countless people losing jobs, being expelled from school for wearing blackface (google news search blackface), many people still either do not understand the difference between blackface and "a black face", or do not understand the origins and why it is so heavily connected to the institutional racism through American (and most of Western) history.

Blackface became popular in minstrel shows in the early 1800's in the US where white actors would paint their face black and exaggerate features like lips and hair to portray black characters. The portrayals were generally mocking black behavior that perpetuated stereotypes that blacks were uncivilized and were better off as slaves. Portrayals included runaway slaves doing things like going into restaurants or trains cars where white people were dining and disturbing their peace.

These performances were often referred to as "Jim Crow" shows after one particular actor brought the Jim Crow character to the stage. Though Jim Crow originated earlier, these shows helped strike fear in whites and perpetuate the idea of the dangerous black freeman.

The Jim Crow shows helped desensitize the public to the horrors of slavery and garnered support for the Jim Crow laws later on (For those unaware, Jim Crow laws were established after the Civil War and the abolition of slavery in the US to segregate the black community from the white community, with separate schools, public transport, workplaces, restaurants, etc. for black and white. Though supposedly "separate but equal", black institutions were consistently underfunded, inferior, or non-existent. These laws existed in some form in the US until the 1960's).

Anyway, the point is, blackface is considered racist because it was popularly used to portray blacks as hapless savages and heavily influenced justification for slavery (white man's burden) and government sponsored discrimination and segregation.

Try to understand how that is different from TriHard (a black face).