Ok, here we go. My thinking here owes a lot to Jason DeLeon from his book The Land of Open Graves (120% recommended, deeply informative and incredibly disturbing); I actually just wanted to quote him but my copy of his book is in the US.
Basically, it's almost always problematic (and I mean this in the practical, "causing concrete harm for migrants" way, not the abstract social-justice use) when outside observers (journalists, anthropologists, pastors) "join" migrant groups, particularly when those outside observers are white Americans. The main reasons:
1 (and this applies to all outside observers): every additional member of a caravan stretches the resources of the group even further. Sure, maybe you bring your own supplies, but inevitably, you're relying on the support network of the group at least in some respects. If nothing else, you're one more person that has to be kept track of; one more body taking up seats while hitchhiking.
Check out this quote from the article: "life is good when you are with people filled with [...] hospitality" (emphasis mine). This sounds like someone who's been taking advantage of that hospitality--and I don't mean to emphasize the negative connotation of "taking advantage" here; obviously hospitality is freely given, and I'm sure Rogers has good intentions, but at the end of the day, he's using resources that could be taking better care of more migrants if he wasn't there.
2 (particularly for white Americans): the presence of someone who's seen as privileged, with access to money and resources, significantly increases the risk that the caravan is targeted by cartels or bandidos looking for political influence or ransom money.
So what's Rogers doing here? Taking pictures with migrants. Reinforcing his pre-existing belief that we need to help refugees. Just... travelling alongside the caravan. Note that the article's subheading "Putting Christian Beliefs Into Action" mostly refers to past projects he or his church has undertaken. What is he doing to support the migrants he's travelling with? It's not clear. So is his presence really helping here?