回复：这篇文章并没说错。楼主的情况有两种处理方式：

1.作为home equity loan，每年100，000可抵税， 见code section 163(h)(3)(C )(i) & (ii).

2.  作为rental property interest expense, 和租金相抵。楼主可以再借10万用于personal
purpose. 如果从其他rental property 里借钱，方式#1就不适用。无论你在何处借的钱，用来买房子的钱就是Acquisition
loan. 那么利息就是acquisition indebtedness interest, see section code 163(h)(3)(B)(i)&(ii) for the rules.
 

此文中也提到：

If treated as passive activity debt, the interest is deductible against the rental income produced by the acquired
property. The limitation of $100,000 on home equity debt does not apply, as the
debt was not incurred for personal purposes.

另外要说的是home mortgage 尽管limited to 1百万，但是你可以借用10万home
equity loan的额度。即在没有home equity loan的情况下，home mortgage 可以抵税1.1million.

此文还讲了Interest 怎么扣税。税务上有5条tracing rules。由于篇幅较长，于楼主issue
无关，先挂起来以后有时间再写。