Although, the merit system has no perfect modality for disbursement and I've seen many users delivering the 50 merits at once to other users. Just like franky1, he enjoys doing that at once. This could be at anyone's discretion since it's flexible, yet, I love it if it is being used wisely and distributed effectively instead of wasting it on just a post while other more meaningful posts are being neglected.
I don't know if there is any method to send merit but for sending merit it must be a good quality post. There is no rule to award merit without merit. To send merit, it must be a good quality post only then merit can be given. I've also seen good quality posts get 50 or more merit majors at once. The posts I saw that sent 50 merits or more were very good quality merit posts. Here the post in which he gave merit was not given in full merit post. It is a misuse of merit.
About your concern, the suspicion here is that the user who sent the merit was a dead horse that just arose again for the purpose of sending the merit. This could indeed be concerning but may not be as we thought of it at times. Regardless of how it is, it is certainly an abuse of merit sharing of the forum, especially when the post merited is not worth any merit, not to mention handing it a whole 50 merits at once. That's gross.
The matter of sending talent is accepted but not so much is accepted in any way. It makes no sense for him to send so many merits to this post. These should be noted. Misuse of merit is that they must be warned against this, not everyone can send merit like this.