As a child, when I first read Hergé's Tintin comic books (graphic novels) in German, and when I still rather tended to enjoy even some of the more politically incorrect and problematic earlier instalments, already at that time (in the late 70s), Tintin au Congo regularly and generally tended to make me both physically and mentally cringe at the blatant stereotyping, the colonialism, the overt and nasty racism depicted (so much so, that I actually never managed to fully finish reading the book until I was a teenager, in 1982, usually giving up in disgust at both the content and the presented thematics of Tintin au Congo, as well as at the frustrating fact that when I would ask my parents about episodes and illustrations that I considered blatant racism, they generally simply claimed that it was a sign of the times and to therefore not worry so much about it). And while, perhaps, my parents were indeed somewhat correct in claiming the latter (that the racism depicted was indeed very much a sign of the times), that does in NO WAY excuse the unfortunate and nasty truth that Tintin au Congo is simply and utterly replete with questionable content and patently unacceptable loathsome euro-centric colonialist attitudes.
Furthermore, aside from the ever-present colonialism and ethnic stereotyping (making almost ALL of the native African characters appear as at best childishly simplistic and at worst corrupt and stupid, not to mention how they have been illustrated, with protruding caricature like lips, and speaking broken pidgin French), there are equally far far too many uncritical, condoning and even positive representations of so-called trophy hunting featured (as basically, Tintin is in Africa not only to tour the continent but also and obviously to seemingly "bag" as many species of animals as possible), and as such, an attitude that Africa as a continent is there for the taking, is there for the manifest destiny of European expansion and use/abuse is definitely to be found in Tintin au Congo (and whether politically or religiously, that really and truly matters not or at least should not matter). And while early children's literature (both novels and illustrated offerings) does indeed contain many similarly questionable details, the fact that Tintin au Congo contains such an all-encompassing amount of the same (massive amounts of dead, of deliberately slaughtered African animal species, as well as almost every page presenting Africans as simpletons, as almost lesser human beings), this in my opinion does make Tintin au Congo negatively and frustratingly stand hugely out.
Now I do well realise some readers as well as literary analysts have often claimed (or have tried to claim) that the overabundance of the ethnic stereotyping, that the colonialism, the over-eager (read extreme) hunting behaviour and practices in Tintin au Congo might, in fact, be of satiric intent, that Hergé (like Jonathan Swift) is showing, is presenting an expanded and hugely deliberately exaggerated portrait of Africa and colonialism in order to criticise, in order to hold up a mirror to society, to the crowned heads of Europe (so to speak). But while this might indeed be partially correct for some of the later Tintin graphic novels (where humour and satiric intent is definitely both present and easily appreciated, easily noticed), the storyline (even if at times somewhat over the top so to speak) of Tintin au Congo really never reads and never feels (at least my humble opinion) as being all that satirical or in any way much actively critical of colonialism (for in Tintin au Congo, the attitude towards Africa and towards Africans is at best massively paternalistic and as such both frustrating and so annoying that I can only and will only consider a one star rating maximum and in fact really would love to grant negative stars). And with regard to recommending Tintin au Congo, I would ONLY EVER and majorly grudgingly suggest Tintin au Congo to and for teenagers and adults (and even then SOLELY for historical and academic research and analysis purposes, for discussions and debates on colonialism and what should in fact NOT be included, should not be featured in children's literature).
Finally, considering recent medical advances (and the fact that we are now rather confident that repeated head injuries, that concussions and the like can and often will lead to serious and lasting cognitive issues and other health related problems), well, the vast amount of times that particularly Tintin throughout the series as a whole is knocked unconscious, is bonked on the head, is drugged, is rendered immobile, is seemingly seriously injured is also to and for me cause for both concern and need for discussion. For Tintin never seems to show ANY major post trauma ill effects, a scenario that is at best a bit naive and at worst potentially dangerous (as it could make readers, but especially children think that the dangers Tintin faces and the injuries he receives are not all that serious, and that therefore, concussions and the like are also not all that serious either, something that might have well been the general consensus when the Tintin books were first published, but an attitude that is definitely not so much the case nowadays, as in fact, rather the opposite seems to be the standard currently accepted position).