  We perform three-body model calculations for soft dipole excitations of the
proton-rich Borromean nucleus $^{17}$Ne. To this end, we assume that $^{17}$Ne
takes the $^{15}$O+p+p structure, in which the two valence protons are excited
from the $0^+$ ground state configuration to $1^-$ continuum states. We employ
a density-dependent contact force for the nuclear part of the pairing
interaction, and discretize the continuum states with the box boundary
condition. We show by explicitly including the Coulomb interaction between the
valence protons that the Coulomb repulsion does not significantly alter the E1
strength distribution. We point out that the effect of the Coulomb repulsion in
fact can be well simulated by renormalizing the nuclear pairing interaction.
