There’s a grim, apologetic vibe to these messages — I’m sorry I’m taking time for myself but I’ll try to check in on occasion! They’re a vivid reflection of a work culture that valorizes constant productivity and the near-total overlap of work and life. But they’re also do a terrible job of what they’re intended to do, e.g., set realistic expectations for both sender and recipient. A vague OOO message traps both parties in an uncomfortable liminal space where both productivity and rest go to die. The original sender is left unsure if they’ll be getting a timely response or a whether the email will go ignored for a time or forever. The original recipient has taken what is a rock solid excuse (time off) and cheapened it, offering a backdoor for email guilt to creep in.
In a role where I got many OoO replies, I actually loved this. (And wrote back in said language. And got a reply!)

Hah! Maternity/parental leave is often 1 year here, so there is zero expectation you will read or “catch up” afterwards. We keep our email addresses during where I work (Canadian government), so it’s standard to put an OOO that just says “on parental leave. Please contact X instead” with no reference to actually reviewing any of those emails, and often not even a projected date of return since people often flex their return date or take extra time, or just return to a different position entirely (out of choice).
Thank you for your email. I will be out of the office from mm/dd to mm/dd and will have limited access to email / will not have access to email. If this is urgent, please contact [NAME] at [EMAIL] or [PHONE]. I will do my best to respond promptly to your email when I return on mm/dd. Why is out of office message important?