This issue exists in consulting, banking, generally in corporate America and East Asia, etc. The "reasons" are grounded in history and a nation's/industry's identity+culture.
It's a problem. It does not breed a productive (or healthy) workforce. But it is a fact.
Now, is it worth worrying about? No. Unfortunately, you're not going to be able to change it (the beast is larger than you). As such, you have two choices:
1) Recognize this, accept it, live with it, and grind it out
2) Recognize this, realize it's not right for you, and find another area to work in.
Option #3 is not an option: i.e. trying to figure out why it is how it is, getting frustrated, trying to fight it, etc.
Hope this makes sense!
P.S. If you're curious about the "why", I have my own thoughts as a bit of a history nerd (cue essay :) )
In terms of countries, the US generally looks down up vacation because it was founded as a capitalistic, meritocractic, "make it on your own" society. When expanding west, you could literally stake your claim on land, and, if you defended it (against the rightful owners to be fair), it was yours.
In East Asia (Japan, S. Korea, Taiwan, Singapore, Hong Kong) as well as Northern Europe, natural resources are scarce (In East Asia this is metals etc., in Northern Europe this is agriculture). As such, you have to work A LOT harder to make ends meet. This results in a super hardworking population as compared to a region with warm weather and plentiful natural crops and animals.
In Industry terms, Bankers and Consultants are "hired guns" motivated by high salaries. They are paid to handle high stress (manage lots of money and/or business-critical decisions), face clients frequently, and be on-call. When you think about it, this breeds the need to be "always on". You're getting paid a lot, in a highly visible job, where dropping the ball within short periods of time can cost lots of money. As such, of course it would be frowned upon to step away from the desk!
Hope this helps :)
PPS: Some MBB regions are rougher than others. BCG Australia had a strong focus on sustainability. They did encourage vacations and were very aware of burnout etc.
Different teams/Partners also dramatically change this as well!