The ubiquitous "they" -- anecdotal and worthless.
Who, in particular? Certainly if this is problematic enough to warrant comment you should find linking to these culprits a fairly trivial task.
So, again: Who?
If you meant "who are these some who oppose this understanding of Allah means Al ilah because they believe Allah is a unique, personal name of God" then the answer is "some Muslims" and of course some "non-muslims" as well.
By asking "in particular" you mean you want names?
Okay. There are four people I can quote who are very famous muslims. Mansur, Adnan Rashid, Hashim, Ahamed Deedat if you are interested in YouTube types. Also if you are looking for a Phd level Muslim who things this I can quote you a guy called Murie Ahamed Hassan in Australia. And if you are looking for a Christian evangelist you would find "Christian Prince" who thinks this.
Any tom, dick or harry who makes a sentence like "The God of the Bible and Allah of the Quran are two different Gods" thinks the same. And that's many. Few of them make this statement out of ignorance, some of course are aware of the linguistics but they intentionally ignore it for the pleasing of an audience. For example Ali Sina and Abdul Fadi.
There are authors like Bill Warner and Robert Spencer who thinks the same. Robert Morey used to but now he is silent on the issue after some exposure. Yet they ignore the fact that the arabic bible translates Elohim as Allah.
If you like to read a bit of a synopsis to understand further you can read Gerhard Bowering snippet in the book encyclopaedia of Islam.