You are currently asking two questions at once; that usually does not work very well on this site. I'd focus on the second one; it's more interesting. We have dozens of questions here dealing with peer pressure that you can search for and will probably help you deal with the short term issue. Or you can just ask it separately. Our sister site Interpersonal Skills is also a great resource for dealing with peer pressure and setting boundaries. Also, welcome to the site!

As Daniel points out, 1000 euro really isn't that significant for a company with good revenue. I doubt this money is in the way of the investments you mentioned, have you asked for any of the things you want/need? Don't forget that you will make yourself an enemy to all of the coworkers who are enjoying this trip if you get this to be cancelled.

Spouses or partners are not invited? You seem to imply that by the room sharing information.

@xyious it's stated very clearly that the event is optional and almost half of the company chooses to opt out of it.

I just want to know how I get hired there?

@Summer As the OP said the company does not want to use 1k€ for other, professionally more useful, investments even on the OP that is saving them the 1k€ not going to the trip.

Regarding unfairness of the trip, you could argue the same about basically any other perk too - Standing desks are unfair to those who don't use them. A gym discount is unfair to those who don't gym. A free daycare is unfair to those without children. And so on.

Sharing rooms on business trips and your OK with this ?

I should consider this here in Japan where employees don't take their minimum amount of holidays as mandated by law. It's a big problem.

@thursdaysgeek: no, partners/spouses are not invited.

@Bakuriu He added that much later than I added my comment.

Frame challenge: 50-60 people really seem to enjoy this trip. 50ish decline it, to me peer pressure is a non-issue. Now, estimated cost of 50k EUR per trip is about 1 programmer per year in Netherlands, that 1% staff. IMHO it's way better to keep 50 people on board for this money, trip seems like a factor. This makes the question about changing funding priorities and company culture. People might like the trip better than a lab. It's fine to ask and I have nothing against you personally, but I think that being against trip is a fine personal opinion but not best company policy, consider it.

@luk32: I doubt you can get a decent Programmer in the Netherlands for 50k with overhead I know you can´t in Germany!

I'll agree with luk32: you seem to conflate several ideas here: 1) that the trip presents difficulties to you personally (fact) 2) that joining the trip would be bad for you (questionable) 3) that having the trip is bad for the company (highly questionable). I think any good answer to your questions will have to separate those three very clearly. For instance, before suggesting to scrap it, suggest an evaluation of its costs vs benefits. Company culture isn't unimportant just because you disagree with it.