You are right. White people have the right to be offended if Raheem tweets De bruyne and Zinchenko looks the same. However, it seems that people here are getting offended at people who have been offended by the Silva's tweet.
Also, black people have been on the wrong end of racism for a long time and hence any news concerning them get a lot more publicity, rightly or wrongly.
Same things are being told when Black Lives Matters groups protest and then the All Lives Matters brigade come out saying whites should be treated the same way. The problem is the BLM group started for a reason and that's because of a lot of police shootings in America involves Black People. No one has ever said white people are not shot but you can clearly see there is a racial bias and black people have been the victims of it for quite a long time and still are.