That is ridiculous right? Look at the little sister in MoTH and the daughter in DMD. I don't know why there is that mindset despise the huge success of those two games.
It's because this game is try-harding too much. It's really obvious that it is trying to ride on the success of Milfy City and it is overshadowing everything to the point that it's hurting the game's perception. For a case in point, look at this thread.
"Landlady" plot? check
similar name? check
replica of a main character? check
First point is a given, using a landlady/incest plot is en vogue and normal in this day and age but the rest is creatively bankrupt, plain and simple.
While the product here is good, it feels contrived and lacks personality/individuality. Don't get me wrong, it's perfectly fine to use similar assets and taking inspiration off existing characters. From a business standpoint this even makes complete sense, but the execution is lacking and uninspired.
There are other examples out there where Milfy City has clearly been used as an inspiration as well, look at Echoes of Lust: the mom and both sisters are based off Linda, Caroline and Sara, but the game has a personal touch and a genuine personality which leads to far less criticism and more objective opinions.
tl;dr the game here is good and well made, but it borrows too much from Milfy City and is therefore (sadly) only regarded as plagiarism. It hurts the game unnecessarily.