I don't think this is the right advice. Sending unsolicited private messages is prohibited on the forum. Moreover, many have a ban on receiving letters from newbies. And in general, how will it look like if you write a personal thank you for each post?
In general, about the religion of likes ... Why should everything today look like Facebook and everything should be rated in likes? Many people live for likes, they shoot videos, and so on.
The merit system is more sophisticated and more interesting. Before evaluating someone in terms of likes or dislikes, the user must have his own merits to further evaluate someone. I know that for many newbies it becomes a challenge to get merits, thereby motivating them to create good posts. And also understand how useful the message should be to give credit for it.