“religion is not being forced on others” is incorrect on its face. these trips are for the express purpose of evangelizing and trying to convert poor, exploited people unfortunately. the physical, murderous aspects of colonialism have traded in their tactics for social and cultural colonialism
there will always be religious groups who genuinely help people, religious groups who really have the underlying (or even straightforward) motive of converting people, and religious groups who have the best intentions of helping people but end up either doing harm or helping less than intended in the process. religious missionaries have really always been the same.
Idk Its definitely weird but also it’s one thing to be like “hey we think you should convert to this religion because it helped us and think it will help you” compared to the genocidal campaigns of past colonization. “Spreading the word of god” isn’t the same thing when they’re not people in power and the people they talk to on these mission trips can just say no
A lot of these trips hold resources over the heads of the people, though. Like "you can eat our free food if you listen to us yap about our religion" is the direct precursor to "you aren't allowed to have, remember, or practice your own culture or religion because you need to be One With Our God." Conditional assistance isn’t charity, especially when the condition is "step away from who you are and into who we want you to be"
if you are rewarded materially (food, charity, labour like habitat for humanity does, childcare materials like diapers, etc) for interacting with an evangelizing/missionary group (religious or not) especially as a poor person in a historically exploited country, the evangelizers hold power. especially considering the missionary work being referenced in OP is mostly well off white people from developed nations, there is a power imbalance that is still very insidious